Question

Given the function: f(x) = 2x3 - 3/2x, find f(-4).

A) -134
B) -128
C) -126
D) -122

Answer 1

D) -122

Explanation:

Given:

`f(x) = 2x^3-\frac{3}2x`

We need to find f(-4).

Now by substituting the value of x =-4 in above equation we get;

`f(-4)= 2*(-4)^3-(3)/(2)*(-4)\\`

By using PEDMAS we will solve for exponential function first we get;

Now we know that
`(-4)^3=-64`

So we get;

`f(-4)= 2*(-64)-(3)/(2)*(-4)\\`

Now using PEDMAS we will solve division.

`f(-4)= 2*(-64)-1.5*(-4)`

Now using PEDMAS we solve multiplication.

`f(-4)= -128+6`

Finally by subtraction we get;

`f(-4)= -122`