Find the factors from the roots, then multiply the factors together.

y=x3-3.5x2+3.5x-1

hello:

y=x3-3.5x²+3.5x-1

y = (x3 - 1) - 3.5 (x² - 1)

y = (x - 1) (x² + x + 1) + 3.5 (x - 1) (x + 1)

y = (x - 1) (x² + x + 1 + 3.5x - 3.5)

y = (x - 1) (x² + 4.5x - 2.5)

the dicriminent of x² + 4.5x - 2.5 is : Δ = (4.5) ² - 4 (1) ( - 2.5) = 30.25 = (5.5) ²

x1 = ( - 4.5 - 5.5) / 2 x2 = ( - 4.5 + 5.5) / 2

x1 = - 5 x2 = 1/2 = 0.5

y = (x - 1) (x + 5) (x - 0.5)