-9x+4y=8 ------(equation. 1)
-3x-4=4. -------(equation 2)
(1) + (2)
-12x+3y=12
-4x+y=4
y=4+4x --------(3)
substitute y value in eq (1)
-9x+4(4+4x)=8
-9x+16+16x =8
7x+16=8
7x=-8
x=-8/7
therefore substitute x in eq (3)
y=4+4(-8/7)
y=4-32/7 = 28-32/7
y= -4/7
x=-8/7, y=-4/7.
