Verified answer

c. {4,-4}

because 3 = √x^2-7

9=x^2-7

x^2=16 ==> x=4 or -4

C. {4,-4}

There is no answer in any of those options...

3 = √x^2 - 7.

According to Order of Operation, you must take the sqrt FIRST because squaring and taking the square root have the same order in PEMDAS (parantheses, exponents, multiplication/division, addition / subtraction. So, you would read from left to right.

First, add 7 to both sides.

10 = √x^2

And then square both sides.

100 = x^2

And then square root both sides...

x = +10 or -10

On top of that, everyone above forgot to add 7 to both sides to isolate the x term. That is CRUCIAL to solving equations like this correctly.

9 = x^2 - 7

16 = x^2

x = -4, 4

C

ans ; c. {4,-4}

option d is the answer