solve 20x^2+180x^(-1)-170

Question

find the zeros

Answer 1

20x^2+180/x-170=(20x^3-170x+180)/x. The zeroes are found by solving 20x^3-170x+180=0 or 10(2x^3-17x+18)=0.

When x=2 the expression is zero so we divide by this zero:

2 | 2 0 -17  18

     2 4    8 -18

     2 4   -9 | 0 = 2x^2+4x-9. This quadratic has zeroes x=(-4±√(16+72)/4=1.3452, -3.3452.

Therefore the zeroes are 2, 1.3452, -3.3452