Posted by **Amy** on Sunday, September 12, 2010 at 5:17pm.

Find all roots:

#1.) 2x^3 + 5x^2 - 22x + 15 = 0

#2.) x^4 + 4x^3 + 6x^2 + 8x + 8 = 0

- Math - Find all roots -
**MathMate**, Sunday, September 12, 2010 at 7:02pm
#1

2x^3 + 5x^2 - 22x + 15 = 0

Did you notice that the coefficients of the equation add up to zero?

This means that (x-1) is a factor.

Divide the left-hand-side by (x-1) using long division and solve the resulting quadratic equation by factoring.

#2

If the coefficient of x^4 is 1 and the constant term is 8, the possible real rational factors are (x+1), (x+2), (x+4) or (x+8). Try these factors and reduce the expression by long division. Repeat until no more factors can be found.

Hint: there are two complex roots for this equation, so you will only find two real roots.

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