Big Ideas Math - Algebra 1, A Common Core Curriculum

Published by Big Ideas Learning LLC
ISBN 10: 978-1-60840-838-2
ISBN 13: 978-1-60840-838-2

Chapter 7 - Polynomial Equations and Factoring - 7.6 - Factoring ax^2 + bx + c = 0 - Exercises - Page 395: 25

Answer

$x=-2$ and $x=3$.

Work Step by Step

The given equation is $\Rightarrow 5x^2-5x-30=0$ Factor out $5$. $\Rightarrow 5(x^2-x-6)=0$ Divide each side by $5$. $\Rightarrow \frac{5(x^2-x-6)}{5}=\frac{0}{5}$ Simplify. $\Rightarrow x^2-x-6=0$ Rewrite $-x$ as $2x-3x$. $\Rightarrow x^2+2x-3x-6=0$ Group the terms. $\Rightarrow (x^2+2x)+(-3x-6)=0$ Factor each group. $\Rightarrow x(x+2)-3(x+2)=0$ Factor out $(x+2)$. $\Rightarrow (x+2)(x-3)=0$ Use zero product property. $\Rightarrow x+2=0$ or $x-3=0$ Solve for $x$. $\Rightarrow x=-2$ or $x=3$ Hence, the solutions are $x=-2$ and $x=3$.
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