# Question #557a2

Sep 30, 2016

$= 7 {a}^{2} d + 2 y + {y}^{2}$

#### Explanation:

Count the number of terms first.
Look for like terms. Only terms that have exactly the same variables can be added.

$10 {a}^{2} d + 2 y - 3 {\mathrm{da}}^{2} + {y}^{2} \text{ } \leftarrow$ has 4 terms

$= \textcolor{red}{10 {a}^{2} d - 3 {a}^{2} d} + 2 y + {y}^{2} \text{ } \leftarrow$ variables in alphabetical order.

$= \textcolor{red}{7 {a}^{2} d} + 2 y + {y}^{2} \text{ } \leftarrow$ like terms added