The problem is to find the roots of the cubic equation $x^3 + 11x^2 + 28x = 0$.

AlgebraCubic EquationsRoots of EquationsFactoringPolynomials
2025/3/25

1. Problem Description

The problem is to find the roots of the cubic equation x3+11x2+28x=0x^3 + 11x^2 + 28x = 0.

2. Solution Steps

We are given the equation x3+11x2+28x=0x^3 + 11x^2 + 28x = 0.
First, we can factor out an xx from each term:
x(x2+11x+28)=0x(x^2 + 11x + 28) = 0.
This tells us that one solution is x=0x=0.
Next, we need to factor the quadratic x2+11x+28x^2 + 11x + 28.
We look for two numbers that multiply to 28 and add to
1

1. These numbers are 4 and 7, since $4 \cdot 7 = 28$ and $4 + 7 = 11$.

Therefore, we can factor the quadratic as (x+4)(x+7)(x+4)(x+7).
The equation becomes x(x+4)(x+7)=0x(x+4)(x+7) = 0.
Setting each factor to zero gives the roots:
x=0x = 0, x+4=0x+4 = 0 which means x=4x = -4, and x+7=0x+7 = 0 which means x=7x = -7.
The roots are 0,4,70, -4, -7.

3. Final Answer

0, -4, -7

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