Given a function y = -2x³ find the value of the argument if y = 16 and y = -2.

First, we express the values of the argument X through the value of the function Y:

Y = – 2 x X³;

X³ = Y / (- 2);

X = ³√ (Y / – 2).

This is in general terms. Now you can calculate special cases for the values Y1 = 16 and Y2 = – 2:

X1 = ³√ (16 / – 2);

X1 = ³√ – 8;

X1 = – 2;

X2 = ³√ (- 2 / – 2);

X2 = ³√ 1;

X2 = 1.

Answer: when the value of the function is 16, the value of the argument is – 2; when the function value is – 2, the argument value is 1.