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# why is the value 7 of this math problem?

√9 + √16 Why is the answer 7?

### 8 Answers

- RaymondLv 79 years agoFavorite Answer
Unless there are reasons to do otherwise, we normally use only the positive value of square roots.

I know that -3 is also a square root of 9

because (-3) * (-3) = +9

therefore, -3 does meet the requirements of being a square root of 9.

Technically, there could be 4 answers to the problem:

+7, +1, -1 and -7

But, unless you have a good reason to take something other than +7, then we take only the positive value of each root, and add them together.

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In solving a quadratic equation, we need the two roots (because we either solve the intersection of the graph with the x-axis -- and there are ususally two such intersections -- or we find linear factors and there are usually two); that is why in solving a quadratic, we will use both "plus or minus" the square root.

- RonLv 69 years ago
The square root of 9 = 3 and the square root of 16 =4 and so the reason why the value is 7 is because you would use addition to solve the problem hence 4+3=7.

- Anonymous9 years ago
Each square root has an integer value. The square root of 9 is 3, the square root of 16 is 4. So adding them gives 3 + 4 = 7.

- Anonymous9 years ago
the square root of 9 is 3, and the square root of 16 is 4, therefore 3 +4 is 7. that is why the answer is 7

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- 9 years ago
Well you see, half of 9 is 3 right, and half of 16 id 4. the add them up and you get 7