x³ - 2x² - 5x = 0
First, take common factor:
x(x^2 - 2x - 5 )= 0
Now use the quadratic formula to find the roots of the trinomial
x = [- b +/- √(b^2 - 4(a)(c)] / 2a
\(x = \frac{2 +/- \sqrt{4 -4(1)(-5)} }{2}\)
x = [2 +/-2√6 ]/2
x = 1 + √6 and x = 1 -√6
Then the solutions are:
x =0; x = 1 + √6; x = 1 - √6
That is the las option shown.
