Question

3x^3-x^2+9x-3=0
this equation has 3 roots, how can we find them by using the quadratic formula?

Answer 1

Why do you need the quadratic formula to find them?

Answer 2

well...do you have a better way to find the three roots? i want to try it with the quadratic formula

Answer 3

You don't use the quadratic formula for a cubic

Answer 4

we can, it will be like 3x^2-x+9=0

Answer 5

3x^3-x^2+9x-3=0
x^2(3x - 1) + 3(3x - 1) = 0
(3x - 1)(x^2 + 3) = 0
3x - 1 = 0
x^2 + 3 = 0

You can use quadratic formula to figure out the roots for x^2 + 3 = 0

Answer 6

so the roots are 3 rooted, and 1/3... wheres the third? to the original equation

Answer 7

x = -sqrt(3)
x = +sqrt(3)
x = 1/3