Question

Find the Error A student evaluated the

expression (x2-y)³ if x = -4 and y = 7.
Find his mistake and correct it.
(x^2-y²=(-42-73
=(-16-7)³
= (-23)³
= -12,167

Answer 1

The student made a mistake when squaring -4.

-4 * -4 = 16. Had the expressions said -x^2, then the answer would indeed be -16 since -1 *(-4*-4) = -16

Furthermore, since the answer is 16, you'd do (16 - 7) ^3, which equals (9)^3, which is 729 and not -12,167