Answer
$-99$
Work Step by Step
We are given: $x=-1$, $y=2$, $z=-3$
We take into account the order of operations:
Parenthesis, Exponents, Multiplication/Division, Addition/Subtraction
Thus, we have:
$$(3x-4z)(2x+3z)=(3(-1)-4(-3))(2(-1)+3(-3))\\
=(-3+12)(-2-9)=9(-11)=-99
.$$
