Question

If 4x-2y>3 and 2x-2y<18, which must be true?

Answer 1

let's say 2y < 18 - 2x
so 
4x - 2y > 3
4x - 18 - 2x > 3
2x > 21
2x/2 > 21/2
x > 10.5

2y < 18 - 2(10.5)
2y < 18 - 21
2y < -3
y < 1.5