D) 21
1) In this problem, to satisfy this condition, we need to plug into the 2nd equation that ordered pair.
2) Therefore, we can write out this:
[tex]\begin{gathered} I)\:x-2y=-4 \\ II)\:3x+5y=Q\Rightarrow3(2)+5(3)=Q\Rightarrow Q=21 \\ \end{gathered}[/tex]3) Thus, the answer is D. 21