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