Answer:
You have to use the subsitution method
Step-by-step explanation:
so it's telling you what the y value is an you have to subsitute 6x-b where the y is.
so the new eqaution would be -3x+1/2(6x-b)=-3
-3x+3x-b=-3
-b=-3
b=3
the b is the in y=x+b
