-x + 9 x - 3 x + 4 ------ + ----- > ----- 8 5 20
(9 - x)/8 + (x - 3)/5 > (x + 4)/20
And(-13 < x, x < oo)
(-13 < x)∧(x < oo)
(-13, oo)
x in Interval.open(-13, oo)