-7 < 7 - 2x <=5
-7 -7 <-2x <= 5 - 7
-14 < -2x <= -2
-14/-2 > x >= -2/-2
1 <= x < 7
x∈[1, 7)
3x-2y=8 3x-2y=8 3x-2y=8 y=3-2x y=3-2*2 y=-1
6x+3y=9 3y=9-6x y=3-2x 3x-2(3-2x)=8 x=2
3x-6+4x=8
7x=14
x=2