we have the system
× = -4y -1 ------> equation A
4x -3y =91 -----> equation B
substitute equation A in equation B
so
4(-4y-1)-3y=91
solve for y
-16y-4-3y=91
-19y=91+4
-19y=95
y=-5
Find the value of x
x=-4(-5)-1
x=19
