y= 1/2x + 1/3
1)
y(0) = 1/2 * 0 + 1/3 = 1/3
y(2) = 1/2 * 2 + 1/3 = 1 1/3
1/3 < 1 1/3
2)
y(1) = 1/2 * 1 + 1/3 = 5/6
y(-1) = 1/2 * -1 + 1/3 = -1/6
5/6 > -1/6
