Question

Solve using substitution.
4a=3b+3
a=b-1

Answer 1

4a=3b+3 
Put a=b-1 in the above equation 
4(b-1) = 3b+3 
open the brackets 
4b - 4 = 3b + 3 
collect B-terms together on one side 
4b - 3b = 3+4 
b = 7

Answer 2

4(b-1)=3b+3
4b-4=3b+3 -- subtract 3b from both sides
b-4=3 -- add 4 to both sides

b=7
Substitute b into equation 2
a=b-1
a=7-1

a=6

Verify:
4(6)=3(7)+3
24=21+3
24=24 -- True.