Finite Math and Applied Calculus (6th Edition)

Published by Brooks Cole
ISBN 10: 1133607705
ISBN 13: 978-1-13360-770-0

Chapter 0 - Section 0.5 - Solving Polynomial Equations - Exercises - Page 30: 22

Answer

Solution set: $\{-1-\sqrt{3}, -1+\sqrt{3}\}$

Work Step by Step

Multiply both sides with $-2$ (2 is the common denominator, and we like the leading term to be positive) $x^{2}+2x-2=0$ Quadratic formula, a=$1$, b=$2$, c=$-2$: $x=\displaystyle \frac{-b\pm\sqrt{b^{2}-4ac}}{2a}$ Checking $\Delta=b^{2}-4ac=2^{2}-4(1)(-2)=4+8=12$ $\Delta$ is positive, so there will be 2 real solutions. $x=\displaystyle \frac{-(2)\pm\sqrt{12}}{2(1)}=\frac{-2\pm\sqrt{4\cdot 3}}{2}$ $=\displaystyle \frac{-2\pm 2\sqrt{3}}{2}=\frac{2(-1\pm\sqrt{3})}{2}=-1\pm\sqrt{3}$ $x=-1-\sqrt{3}$ or $x=-1+\sqrt{3}$ Solution set: $\{-1-\sqrt{3}, -1+\sqrt{3}\}$
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