(x, y) = (-1, 4)
We assume your two equations are ...
You can eliminate the y-variable by multiplying the first equation by 3 and adding the second.
3(7x +y) +(2x -3y) = 3(-3) +(-14)
23x = -23 . . . . . . . simplify
x = -1 . . . . . . . . . . . divide by 23
7(-1) + y = -3 . . . . . substitute for x in the first equation
y = 4 . . . . . . . . . . . add 7