Question

Graph the system of equations to find the solutions of x3 + 6x2 - 40x = 192.

y = x3 + 6x2 - 40x

y = 192

Select all of the solution(s) to the equation.

x = –8

x = –4

x = 0

x = 6

x = 192

Answer 1

Solve x^3 + 6x^2 − 40x = 192 by moving 192 to one side:
x^3 + 6x^2 − 40x − 192 = 0.

Test x = −8: it gives 0, so (x + 8) is a factor. Divide to get
(x + 8)(x^2 − 2x − 24) = 0,
and x^2 − 2x − 24 = (x − 6)(x + 4).

Thus the solutions are x = −8, −4, 6.

Select: x = –8, x = –4, x = 6.