Answer
$\displaystyle \frac{-15}{x}+\frac{4}{x}.$,
simplifies to $\displaystyle \frac{-11}{x}$
Work Step by Step
the quotient of $-15$ and a number ... $\rightarrow$... $\displaystyle \frac{-15}{x}$
...which is increased by ... $\rightarrow \displaystyle \frac{-15}{x}+...$
.... the quotient of $4$ and a number$\quad\rightarrow \displaystyle \frac{-15}{x}+\frac{4}{x}.$
This simplifies, because the demominator is common, to,
$...=\displaystyle \frac{ -15+4}{x}$
... then, adding different signed numbers,
we keep the sign of $-15$, because it has the greater absolute value,
and subtract their absolute values:
$=\displaystyle \frac{-(15-4)}{x}$
$=\displaystyle \frac{-11}{x}$