Answer:
Option A
Step-by-step explanation:
Step 1: Naming both equations:
[tex]Eq. 1: 3x + 2y=-21\\Eq. 2 : x-3y=4[/tex]
Step 2: Isolating x in Eq. 2
[tex]x=3y+4[/tex]
Step 3: Replacing x in Eq. 1
[tex]3(3y+4)+2y=-21[/tex]
Therefore, the answer is Option A