Multiply the 1st row by 4
28x + 20y = 36
4x - 3y = 11
Multiply the 2nd row by 7
28x + 20y = 36
28x - 21y = 77
Subtract the 2nd row from the 1st row
41y = -41
Solve for y in the above equation
y = -1
Substitute y = -1 into any of the two equations above.
Let's pick the first equation; 28x + 20y = 36
28x + 20 × -1 = 36
Solve for x in the above equation ^
x = 2
Thus;
x = 2
y = -1