1) 4х+7у=22 4х=22-7у х=(22-7у)/4
х=0 => y=3 1/7
x=1 => y=2 4/7
x=-1 => y=3 5/7
(0; 3 1/7) (1; 2 4/7) (-1;3 5/7)
2)x=5; e=-2
7x+2y=35-4=31 7x+2y=31
3)-4x=5y=28 4x=5y-28 x=(5y-28)/4=1.25y-7
4) 7x+2y=-8 2y=-8-7x y=-4-3.5x
a) x=-2 => y=-3
b)x=0 => y=-4
c)x=6 => y=-2.5
5) A(x=0; y=-3)
B(x=1; y=0)
C(x=2; y=3)