Answer:
n= -6, a= 5
Step-by-step explanation:
Label the two equations:
a= -2n -7 -----(1)
-3a +n= -21 -----(2)
Substitute (1) into (2):
-3(-2n -7) +n= -21
Expand:
-3(-2n) -3(-7) +n= -21
6n +21 +n= -21
Simplify, minus 21 on both sides:
7n= -21 -21
7n= -42
Divide both sides by 7:
n= -42 ÷7
n= -6
Substitute n= -6 into (1):
a= -2(-6) -7
a= 12 -7
a= 5
