[译] X² = 16 (X = +4 或 X = -4) 有二者选一的答案。
[误] There are alternate answers to X² = 16 (X = +4 or X = -4)

[正] There are alternative answers to X² = 16 (X = +4 or X = -4)
[注] alternate 意为"交互的"、"间隔的"，如：She comes here on alternate days. 她隔日到这里来。alternative 意为"二者选一的"，又如：We have only two alternative courses; success or failure. 我们只有两条路可以选择：要么成功，要么失败。