# Evaluate for b= -2. (-4b - 8) + (-1 -b^2) + 2b^3

## Question:

Evaluate for b= -2.

{eq}(-4b - 8) + (-1 -b^2) + 2b^3 {/eq}

## Evaluating an Expression:

If an expression that is in terms of one or more variables is to be evaluated at the given values of the variables, we have to substitute the given values in it and simplify it.

The given expression is {eq}(-4b - 8) + (-1 -b^2) + 2b^3 {/eq}.

Substitute {eq}b=-2 {/eq} in this expression:

\begin{align} (-4(-2) - 8) + (-1 -(-2)^2) + 2(-2)^3 & = (8-8)+(-1-4) + 2(-8) \\[0.3cm] &=0 +(-5)+(-16) \\[0.3cm] &= \boxed{\mathbf{-21}} \end{align}