Hello there! The value of x is 20 or -20
"20 or - 20" is one answer so you are supposed to answer 20 or -20, not choose only one.
Explanation:
![\large{ \frac{ {x}^(2) }{ {5}^(2) } = {4}^(2) }](https://img.qammunity.org/2022/formulas/mathematics/high-school/lf0zp1n7fkv5a5wy5zcq6d9gvib7f4t8gi.png)
First, we simplify 5² and 4²
![\large{ \frac{ {x}^(2) }{25} = 16}](https://img.qammunity.org/2022/formulas/mathematics/high-school/k80cqvttjq8mveeuv90485l67w8sxuf8xu.png)
Multiply the whole equation by 25 to get rid of the denominator.
![\large{ \frac{ {x}^(2) }{25} (25) = 16(25)} \\ \large{ {x}^(2) = 400}](https://img.qammunity.org/2022/formulas/mathematics/high-school/wixd4gyvwov5otqaityhvhzbq421sqzenb.png)
Square both sides and solve the equation.
![\large{ \sqrt{ {x}^(2) } = \pm{ √(400) }}](https://img.qammunity.org/2022/formulas/mathematics/high-school/iawmce47ouwchkeyinqih657cml9n4z5tr.png)
Also don't forget to write "plus or minus" symbol when we are solving a quadratic equation by squaring both sides.
![\large{x = \pm{20}}](https://img.qammunity.org/2022/formulas/mathematics/high-school/6skfo4f9rptcxcu8hp4cebhknlwwvwwb4u.png)