# How do you simplify -4sqrt(28x)*sqrt(7x^3)?

Aug 14, 2016

$- 56 {x}^{2}$

#### Explanation:

When multiplying two square roots, we can multiply them into one root.
Write the numbers as the product of prime factors.

$- 4 \sqrt{28 x} \cdot \sqrt{7 {x}^{3}} = - 4 \sqrt{2 \times 2 \times 7 \times 7 \times {x}^{4}}$

=$- 4 \times 2 \times 7 \times {x}^{2} = - 56 {x}^{2}$