# How do you multiply  (a+b)^2?

Apr 3, 2018

${a}^{2} + 2 a b + {b}^{2}$

#### Explanation:

${\left(a + b\right)}^{2}$ is the same as $\left(a + b\right) \left(a + b\right)$.
(It's always easier to write it out because it makes you see clearly all the numbers you are multiplying. Also you'll make less mistakes that way.)

$a \cdot a = {a}^{2}$

$a \cdot b = a b$

$b \cdot a = a b$

$b \cdot b = {b}^{2}$

Combining that all together:
${a}^{2} + a b + a b + {b}^{2}$

However we can still simplify the $a b + a b$ into $2 a b$. Therefore, the answer is ${a}^{2} + 2 a b + {b}^{2}$.

Hope this helps!