3y+4x=76
3y+4x-4x=76-4x
3y=76-4x
3y/3=76-4x/3
y=25.33-1.33x
4y + 7x = 128
4(25.33-1.33x) + 7x = 128
4(25.33) (4)(-1.33x) + 7x = 128
101.32-5.32+7x=128
96+7x=128
96+7x-96=128-96
7x=32
7x/7=32/7
x=4.6
y=25.33-1.33x
y=25.33-1.33(4.6)
y=25.33-6.12=19.2