Question

What value(s) of x will make x2 = 81 true?

Answer 1

Yo have to determine the value of x that makes the following statement correct:

$x^2=81$

To determine wich values are correct you have to replace the values in the formula and see the result:

For x=9

$9^2=9\cdot9=81$

For x=40.5

$40.5^2=40.5\cdot40.5=1640.25$

For x=-40.5

$(-40.5)^2=(-40.5)(-40.5)=1640.25$

For x=-9

$(-9)^2=(-9)\cdot(-9)=81$

For x=3

$3^2=3\cdot3=9$

For the values 9 and -9 is x²=81 true. The correct answer is C