108X^4 - 90X^3 = 0
factor out X^3
X^3(108X - 90) = 0
108X - 90 = 0
108X = 90
x = 5/6
---------
x = 0
My TI-84 graphs the original equation to these answers
90 - 90 = 0
30 minus 90 is negative 60, if I'm correct.
90/5 = 1818/2 = 9
90 - 55 = 35
90 - 45 = 45
90 - 80 = 10
90 - 72 = 18
90 - 70 = 20
1115 - 90 = 1025
3.36 - 90 = -86.64
90 - 6 = 84
45