Question

Which equations are true for x = –2 and x = 2? Select two options

x2 – 4 = 0
x2 = –4
3x2 + 12 = 0
4x2 = 16
2(x – 2)2 = 0

Answer 1

Evaluate each with x = ±2 (x^2 = 4):

- x^2 − 4 = 0 → 4 − 4 = 0 (true)
- x^2 = −4 → 4 ≠ −4 (false)
- 3x^2 + 12 = 0 → 3·4 + 12 = 24 ≠ 0 (false)
- 4x^2 = 16 → 4·4 = 16 (true)
- 2(x − 2)^2 = 0 → for x = 2 gives 0 (true), but for x = −2 gives 2·16 = 32 (false)

So the two that are true for both x = −2 and x = 2 are: x^2 − 4 = 0 and 4x^2 = 16.