Answer
$\frac{7}{y}$
Work Step by Step
$\frac{15}{y^2 + 3y} +\frac{2}{y} +\frac{5}{y+3} $
$=\frac{15}{y(y + 3)} +\frac{2}{y} +\frac{5}{y+3} $
$=\frac{15 + 2\times (y+3) + 5\times y}{y(y+3)}$
$=\frac{7y + 21}{y(y+3)}$
$=\frac{7(y + 3)}{y(y+3)}$
$=\frac{7}{y}$