Precalculus (6th Edition)

Published by Pearson
ISBN 10: 013421742X
ISBN 13: 978-0-13421-742-0

Chapter 1 - Equations and Inequalities - Chapter 1 Test Prep - Review Exercises - Page 178: 49

Answer

$\color{blue}{\bf{76\text{; two distinct irrational solutions}}}$

Work Step by Step

Add $3$ to both sides to obtain: $$-6x^2+2x+3=0$$ This this equation has $a=-6$, $b=2$, and $x=3$. RECALL: (1) The discriminant is equal to $b^2-4ac$. (2) A quadratic equation has the following types of solutions based on the value of the discriminant: (a) when $b^2-4ac$ is a $\bf{\text{positive perfect square}}$, the equation has $\bf{\text{two distinct rational solutions}}$; (b) when $b^2-4ac$ is a $\bf{\text{positive but not a perfect square}}$, the equation has $\bf{\text{two distinct irrational solutions}}$; (c) when $b^2-4ac$ is $\bf{0}$, the equation has $\bf{\text{one rational solution (a double solution)}}$; (d) when $b^2-4ac$ is $\bf{\text{negative}}$, the equation has $\bf{\text{two distinct non-real complex solutions}}$; The discriminant of the equation above is: $$b^2-4ac$$ $$2^2 - 4(-6)(3)$$ $$4+72=\color{blue}{\bf{76}}$$ The discriminant is $\bf{\text{positive but not a perfect square}}$. Thus, the given equation has $\color{blue}{\bf{\text{two distinct irrational solutions.}}}$
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