Answer
$\displaystyle \frac{2y-1}{y+3}$
Work Step by Step
To add rational expressions with the same denominator,
add numerators and place the sum over the common denominator.
If possible, factor and simplify the result.
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$\displaystyle \frac{y^{2}-2y}{y^{2}+3y}+\frac{y^{2}+y}{y^{2}+3y} = \displaystyle \frac{y^{2}-2y+y^{2}+y}{y^{2}+3y}$
$= \displaystyle \frac{2y^{2}-y}{y^{2}+3y}$
$= \displaystyle \frac{y(2y-1)}{y(y+3)}\qquad$... reduce the common factor
$=\displaystyle \frac{2y-1}{y+3}$
