Factor.
-$20 z ^ { 2 } - 3 z - 9$
A) $( 4 z + 3 ) ( 5 z - 3 )$
B) Prime
C) $( 4 z - 3 ) ( 5 z + 3 )$
D) $( 20 \mathrm { z } - 3 ) ( \mathrm { z } + 3 )$

Question

Quizplus · Accepted Answer

Using the AC method, we need to find two numbers that multiply to -180 and add up to -3. These numbers are -15 and 12. We can then split the middle term and factor by grouping:
\begin{align*}
20 z ^ { 2 } - 3 z - 9 &= 20z^2 - 15z + 12z - 9 \
&= 5z(4z-3) + 3(4z-3) \
&= (5z+3)(4z-3)
\end{align*}
Therefore, the answer is choice C.

Factor - 20z2−3z−920 z ^ { 2 } - 3 z - 920z2−3z−9

Factor
- $20 z ^ { 2 } - 3 z - 9$