x^4-7x-18x=0
The first floor is right - the four roots are:
X (X & # 179; - 25) = 0, the solution is: X1 = 0, X2 = 179; √ 25, X3 = X4 = - & # 179; √ 25
26.4 x + 18x = 66.6
44.4X=66.6
X = 66.6 divided by 44.4 = 1.5
26.4x + 18x = 66.6
44.4x=66.6