Answer
$-8x^2+3xy+(-9x)+(-3)$
Work Step by Step
To turn the example into an addition problem (a sum), change the minus signs to plus signs, and then change the sign of each of the following terms.
$\ \ \ \ \ \ \ \ \ $subtract 3 becomes add -3
$-8x^2+3xy\underset\uparrow-9x\overset\downarrow-3=-8x^2+3xy+(-9x)+(-3)$
$\ \ \ \ $subtract 9x becomes add -9x
