Answer
$-9x+(-11)x$,
simplifies to $-20x$
Work Step by Step
the product of $-9$ and a number ... $\rightarrow$... $-9x$
...which is increased by ... $\rightarrow -9x+...$
.... the product of $-11$ and a number$\quad\rightarrow -9x+(-11)x.$
This simplifies, first using the distributive property,
$...=[ -9+(-11)]x$
... then, adding same signed numbers, we keep the sign and add their absolute values:
$=-(9+11)x$
$=-20x$
