Q. Solve the equation by factoring:8x+7x2−x3=0Answer: x=
Rewrite in standard form: Rewrite the equation in standard form.The standard form of a polynomial is to have the terms in descending order of their exponents. The given equation is already in standard form: −x3+7x2+8x=0.
Factor out common factor: Factor out the greatest common factor.The greatest common factor in each term is x. Factor x out of the equation: x(−x2+7x+8)=0.
Factor the quadratic: Factor the quadratic equation.Now we need to factor the quadratic equation −x2+7x+8. We are looking for two numbers that multiply to −8 (a⋅c) and add up to 7 (b). These numbers are −1 and 8. So we can write the quadratic as (−x+8)(x+1).
Write factored form: Write the factored form of the original equation.Now that we have factored the quadratic, we can write the entire factored form of the original equation as x(−x+8)(x+1)=0.
Set equal and solve: Set each factor equal to zero and solve for x. We have three factors: x, −x+8, and x+1. Setting each factor equal to zero gives us the equations x=0, −x+8=0, and x+1=0.
Solve for x: Solve each equation for x.Solving x=0 gives us the root x=0.Solving −x+8=0 gives us x=8.Solving x+1=0 gives us x=−1.
Write roots: Write the roots in simplest form.The roots of the equation are x=0, x=8, and x=−1.
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