# How do you multiply (7x-5y)^2?

Sep 15, 2016

$= 49 \cdot {x}^{2} - 70 \cdot x \cdot y + 25 \cdot {y}^{2}$

#### Explanation:

$\ldots \ldots \ldots \ldots \ldots \left(7 x - 5 y\right) \cdot \left(7 x - 5 y\right)$

$\ldots \ldots \ldots \ldots \ldots . = 49 \cdot {x}^{2} - 35 \cdot x \cdot y - 35 \cdot x \cdot y + 25 \cdot {y}^{2}$

$\ldots \ldots \ldots \ldots \ldots . = 49 \cdot {x}^{2} - 70 \cdot x \cdot y + 25 \cdot {y}^{2}$

Sep 15, 2016

$49 {x}^{2} - 70 x y + 25 {y}^{2}$

#### Explanation:

Write as: $\textcolor{b l u e}{\left(7 x - 5 y\right)} \textcolor{b r o w n}{\left(7 x - 5 y\right)}$

Multiply everything inside the right brackets by everything in the left brackets.

Notice that the minus follows the $\textcolor{b l u e}{- 5 y}$

$\textcolor{b r o w n}{\textcolor{b l u e}{7 x} \left(7 x - 5 y\right) \text{ } \textcolor{b l u e}{- 5 y} \left(7 x - 5 y\right)}$

$49 {x}^{2} - 35 x y \text{ } - 35 x y + 25 {y}^{2}$

$49 {x}^{2} - 70 x y + 25 {y}^{2}$