Question 37417
Both of these equations are true when x=1 and y=4.  So a+4b=13 and a-4b=-3.
By the second equation, a=4b-3, so we can use that in the first and get (4b-3)+4b=13
8b-3=13
8b=16
b=2
a+4b=13, so a+4(2)=13, so a+8=13, so a=5.
So a=5, b=2.