First you need to multiply 36 *$30.22=$1087.92
This gives you the total amount paid
Then subtract 1087.92-900=187.92
This gives you the amount of money you paid in finance charges.
X=2y+11 and 4x+3y=11 so choose one of them. I choose x=2y+11 and solve it like this 4(2y+11)+3y=11
8y+44+3y=11
11y=-33
y=-3