2 Answers

Pramod Sivadas · Answer 1 · 2020-03-21T02:12:39+0000

Answer: second option.

Explanation:

Given the following equation:

(x+10)^2=256

You need to find the value of "x" in order to find the side measure of the original square photo.

Knowing that:

(a+b)^2=a^2+2ab+b^2

You can expand the equation:

$(x+10)^2=256\\\\x^2+2(x)(10)+10^2=256\\\\x^2+20x+100=256$

The next step is to subtract 256 from both sides of the equation:

$x^2+20x+100-256=256-256\\\\x^2+20x-156=0$

Now you can factor the quadratic equation. Find two numbers whose sum is 20 and whose product is -156. These are 26 and 6:

$(x+26)(x-6)=0\\\\x_1=-26\\\\x_2=6$

Choose the positive value.

Therefore, the dimensions of the original square photo were:

$6\ inches\ by\ 6\ inches$

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