Simplifying square roots | Algebra (video) | Khan Academy (2024)

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  • sahimwallace

    11 years agoPosted 11 years ago. Direct link to sahimwallace's post “At 0:28, you added all th...”

    At

    Simplifying square roots | Algebra (video) | Khan Academy (2) 0:28

    , you added all the values and observed that if the sum was divisible by 3, so was the value. What video can I find this principle?

    (193 votes)

    • Sam

      10 years agoPosted 10 years ago. Direct link to Sam's post “The link is broken, here ...”

      Simplifying square roots | Algebra (video) | Khan Academy (5)

      Simplifying square roots | Algebra (video) | Khan Academy (6)

      Simplifying square roots | Algebra (video) | Khan Academy (7)

      The link is broken, here is the new one:
      https://www.khanacademy.org/math/pre-algebra/factors-multiples/divisibility_tests/v/divisibility-tests-for-2-3-4-5-6-9-10

      (128 votes)

  • Nathan Shapiro

    10 years agoPosted 10 years ago. Direct link to Nathan Shapiro's post “At 0:09, Sal said that 11...”

    At

    Simplifying square roots | Algebra (video) | Khan Academy (9) 0:09

    , Sal said that 117 is not a perfect square. What does that mean?

    (42 votes)

    • я̿€̿ρ̿Ł̿ɪ̿т̿Ǻ̿ƶ̿

      10 years agoPosted 10 years ago. Direct link to я̿€̿ρ̿Ł̿ɪ̿т̿Ǻ̿ƶ̿'s post “A perfect square is a squ...”

      Simplifying square roots | Algebra (video) | Khan Academy (12)

      Simplifying square roots | Algebra (video) | Khan Academy (13)

      Simplifying square roots | Algebra (video) | Khan Academy (14)

      A perfect square is a square root is not a decimal. You can not take the square root of 117 and have it not be a decimal. But if you were to take the square root of 9, it would be 3 because 3x3=9. Hope this helped!

      (63 votes)

  • Matt Stringer

    6 years agoPosted 6 years ago. Direct link to Matt Stringer's post “I'm having a LOT of troub...”

    I'm having a LOT of trouble siplifying square roots and I can't understand why it's not making any sense to me...
    The Square Roots Practice I can finish in about 10 seconds but I'm really hitting a wall with the Simplification side of Square Roots. Please help me!

    (60 votes)

    • learn

      6 years agoPosted 6 years ago. Direct link to learn's post “I will try to give you a ...”

      Simplifying square roots | Algebra (video) | Khan Academy (18)

      Simplifying square roots | Algebra (video) | Khan Academy (19)

      I will try to give you a couple of examples to help you. If you have a perfect square like √4 you know 2*2 = 4 so √4=2
      but what if you had √12? It isn't a perfect square but it can still be simplified by finding any perfect squares within it and removing them. To see if we have any perfect squares we can do a prime factorization of 12. 12 = 2*2*3 Since we have a perfect square within the 12 we can say √12 = √4*3
      so √12 = 2√3 (The 3 is prime and can't be reduced and the 2 used to be under the radical as √4).
      Let's take √6 now. Prime factorization is √2*3 (We can't remove a perfect square so √6 is already in simplest form.
      Let's take √24 now. Prime factorization is √2*2*2*3 (We have two 2's so we have a perfect square.) We can simplify this to √4*6 or 2√6
      So to simplify a square root use prime factorization to find any perfect squares that you can remove from the total under the radical.

      (48 votes)

  • я̿€̿ρ̿Ł̿ɪ̿т̿Ǻ̿ƶ̿

    10 years agoPosted 10 years ago. Direct link to я̿€̿ρ̿Ł̿ɪ̿т̿Ǻ̿ƶ̿'s post “Wouldn't the answer to a ...”

    Wouldn't the answer to a square root really be positive and negative? For instance, if we wanted the square root of 9, it would be 3 and -3? because 3x3=9 and -3x-3=9?

    (34 votes)

    • Rohini

      10 years agoPosted 10 years ago. Direct link to Rohini's post “Yes, whenever you take sq...”

      Simplifying square roots | Algebra (video) | Khan Academy (23)

      Simplifying square roots | Algebra (video) | Khan Academy (24)

      Yes, whenever you take square roots, you get two values (one positive and the other negative). But when you take the "principle" square root , you take only the positive value.

      (46 votes)

  • andrea baek

    10 years agoPosted 10 years ago. Direct link to andrea baek's post “Around 2:24, Sal explains...”

    Around

    Simplifying square roots | Algebra (video) | Khan Academy (26) 2:24

    , Sal explains that 5*3 and the square root of thirteen is 15 times the square root of thirteen. Why would you multiply the numbers 5 and 3?

    (30 votes)

    • Nathan Shapiro

      10 years agoPosted 10 years ago. Direct link to Nathan Shapiro's post “He is trying to simplify ...”

      Simplifying square roots | Algebra (video) | Khan Academy (29)

      Simplifying square roots | Algebra (video) | Khan Academy (30)

      He is trying to simplify it. 5•3•√13 is more complex than 15•√13. The former has 3 steps involved (multiply 5 and 3, find square root of 13, multiply 15 by square root of 13), while the latter only has 2 steps involved (find square root of 13 and multiply by 15).

      (36 votes)

  • Chris

    9 years agoPosted 9 years ago. Direct link to Chris's post “Which video (and where) e...”

    Which video (and where) explains why you can add up the digits of a number to see if it's divisible by 3 like at

    Simplifying square roots | Algebra (video) | Khan Academy (32) 0:25

    -

    Simplifying square roots | Algebra (video) | Khan Academy (33) 0:36

    ?

    (22 votes)

    • sean

      9 years agoPosted 9 years ago. Direct link to sean's post “go to pre- algabra and in...”

      Simplifying square roots | Algebra (video) | Khan Academy (36)

      Simplifying square roots | Algebra (video) | Khan Academy (37)

      go to pre- algabra and in the factors and multiples section you will find divisablity tests at the top of the list and it explains the rule for 3 in the first video

      (31 votes)

  • AliAfrose

    8 years agoPosted 8 years ago. Direct link to AliAfrose's post “what is the concept of si...”

    what is the concept of simplifying square roots? I don't understand square roots

    (17 votes)

    • Johnathan

      8 years agoPosted 8 years ago. Direct link to Johnathan's post “Roots are the inverse ope...”

      Roots are the inverse operation to powers. So if you take the square root of 6 and then you square it, then you would be left with 6 because the square and the square root cancel out.

      Now if you have the square root of 2 plus the square root of 2, you would have 2√2. Notice that it isn't √4. It is actually 2√2 (which is the same as √8).

      So the concept of simplifying square roots is like the concept of simplifying other things like exponents, parentheses, etc.

      (4 votes)

  • Palaash Dwivedi

    8 years agoPosted 8 years ago. Direct link to Palaash Dwivedi's post “i still don't understand ...”

    i still don't understand the concept

    (13 votes)

    • Jhonella Maceren

      8 years agoPosted 8 years ago. Direct link to Jhonella Maceren's post “I found a website that br...”

      Simplifying square roots | Algebra (video) | Khan Academy (44)

      I found a website that breaks this concept down as if they were teaching it to kindergarten students XD
      https://www.mathsisfun.com/numbers/simplify-square-roots.html

      Helped me finally understand this!

      (21 votes)

  • Vivian

    9 months agoPosted 9 months ago. Direct link to Vivian's post “sometimes i look at the c...”

    sometimes i look at the comments because they're funny.

    (20 votes)

    • Lady Ann

      7 months agoPosted 7 months ago. Direct link to Lady Ann's post “Yup, I also look at the c...”

      Yup, I also look at the comments to give some upvotes. (And maybe a few badges as well)

      (6 votes)

  • Duncan Whitmore

    9 years agoPosted 9 years ago. Direct link to Duncan Whitmore's post “Okay so how would you do ...”

    Okay so how would you do fractions? I'm very confused and my math teacher sped through it so I didn't understand. How would you simplify the sqare root of 35 over 9 (just and example)?

    (12 votes)

    • Jay

      9 years agoPosted 9 years ago. Direct link to Jay's post “The thing about a square ...”

      Simplifying square roots | Algebra (video) | Khan Academy (51)

      The thing about a square root of a fraction is that:
      sqrt(35/9) = sqrt(35)/sqrt(9)
      in other words, the square root of the entire fraction is the same as the square root of the numerator divided by the square root of the denominator. With that in mind, we can simplify the fraction:
      sqrt(35)/3
      As you can see, I left the numerator under the square root, because I can't simplify it, but the square root of 9 is three so I could replace the sqrt(9) in the denominator by 3.
      The same rule applies to exponents: e.g. (2/3)^2=(2^2)/(3^2)

      (12 votes)

Simplifying square roots | Algebra (video) | Khan Academy (2024)

FAQs

How to simplify square root answers? ›

Step 1: Find the prime factors of the number inside the radical sign. Step 2: Group the factors into pairs. Step 3: Pull out one integer outside the radical sign for each pair. Leave the other integers that could not be paired inside the radical sign.

What grade is simplifying square roots? ›

IXL | Simplify square roots | 8th grade math.

How do you get a square root answer? ›

For square roots, find the "reverse" of a square.

When you see a radical, you want to ask yourself, "what number can multiply by itself to give the number under the radical?" For instance, if you see √(9), you want to find the number that can be squared to make nine. In this case, the answer is three, because 32 = 9.

Why do you get two answers when you square root 16? ›

Square root of a number always has two answers, one is positive and one is negative. There are two answers because the square of a negative and positive number is the same.

What grade are you supposed to learn square roots? ›

The lesson suits grades 7-8 and pre-algebra, and is meant for initial instruction on the topic. Finding a square root of a number is like finding the side of a square when the area is known. Square root symbol acts as a grouping symbol: anything under it is in parentheses and is solved first.

What is square root grade 7? ›

The square root of a number is the value of power 1/2 of that number. In other words, it is the number whose product by itself gives the original number. It is represented using the symbol '√ '. The square root symbol is called a radical, whereas the number under the square root symbol is called the radicand.

What grade do you learn algebra? ›

Typically, algebra is taught to strong math students in 8th grade and to mainstream math students in 9th grade. In fact, some students are ready for algebra earlier.

Is there a formula for square root? ›

The square root is an inverse method of squaring a number. Hence, squares and square roots are related concepts. Suppose x is the square root of y, then it is represented as x=√y, or we can express the same equation as x2 = y. Here, '√' is the radical symbol used to represent the root of numbers.

Why is √16 not +-4? ›

Because the output of a square root is always positive. Our answer would be obviously “ohh the square root is always positive so the range is f ≥ 0 “ so -4 cannot be the square root of 16.

What is the rule for square roots? ›

As for square roots, a number r is a square root of a number x if r^2 = x. Based on this definition, a positive number actually has two square roots: a positive number and the negative of that positive number. For example, the numbers 5 and -5 are square roots of 25 because 5^2 = 25 and (-5)^2 = 25.

How to simplify the square root of 145? ›

sqrt(145) No simplification exists, Root remains : • sqrt(145) Simplify : sqrt(145) Factor 145 into its prime factors 145 = 5 • 29 To simplify a square root, we extract ...

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