6x+3y=33..........(1)
4x+y=15
y=15-4x.........(2)
substitute value of y from (2) in (1)
6x+3(15-4x)=33
distribute 3 over the bracket
6x+45-12x =33
-6x=33-45
-6x=-12
x=2
plugging this value of x in equation 2 we get
15-4x=y
15-4(2)=y
y=15-8
y=7
Answer is x=2 and y=7