# How do you simplify (5c^(-4))(-4m^(2)c^(8))?

Oct 8, 2015

$- 20 {m}^{2} {c}^{4}$

#### Explanation:

Key to solving is that: ${c}^{- 4} = \frac{1}{{c}^{4}}$

Rewrite $\left(5 {c}^{- 4}\right) \left(- 4 {m}^{2} {c}^{8}\right)$ as:

$\frac{5}{{c}^{4}} \times \left(- 4 {m}^{2} {c}^{8}\right)$

Giving: $\left(5 \times \left(- 4\right) {m}^{2}\right) \times \frac{{c}^{8}}{{c}^{4}}$ .....( 1 )

But $\frac{{c}^{8}}{{c}^{4}} = {c}^{4}$ ......( 2 )

Substituting ( 2 ) in ( 1 ) gives

$- 20 {m}^{2} {c}^{4}$