# How do you simplify (x + 5)^2?

Aug 28, 2016

$\left(x + 5\right) = \textcolor{b l u e}{{x}^{2} + 10 x + 25}$

#### Explanation:

${\left(x + 5\right)}^{2}$ is a sum of squares, ${\left(a + b\right)}^{2} = {a}^{2} + 2 a b + {b}^{2}$, where $a = x$, and $b = 5$.

Expand.

${\left(x + 5\right)}^{2} = {x}^{2} + 2 \left(x\right) \left(5\right) + {5}^{2}$

Simplify.

$\left(x + 5\right) = {x}^{2} + 10 x + 25$

You can also use the FOIL method to multiply two binomials.

${\left(x + 5\right)}^{2} = \left(x + 5\right) \left(x + 5\right)$

$\left(x + 5\right) \left(x + 5\right) = x \cdot x + x \cdot 5 + 5 \cdot x + 5 \cdot 5$

Simplify.

$\left(x + 5\right) \left(x + 5\right) = {x}^{2} + 5 x + 5 x + 25$

Simplify.

$\left(x + 5\right) \left(x + 5\right) = {x}^{2} + 10 x + 25$