Question 1119517
the second equation is b=4a-1
substitute into the first for b after distributing
3a-3b=15
3a-3(4a-1)=15
distribute
3a-12a+3=15
-9a=12
a=-4/3
4a=-16/3
b=-19/3
(-4/3, -19/3) ANSWER
check in first equation
3(-4/3-(-19/3))=3(15/3)=15