Intermediate Algebra: Connecting Concepts through Application

Published by Brooks Cole
ISBN 10: 0-53449-636-9
ISBN 13: 978-0-53449-636-4

Chapter 8 - Radical Functions - 8.4 Solving Radical Equations - 8.4 Exercises - Page 652: 8

Answer

$x = \frac{23}{3}$ To check if our solution is correct, we plug it into the original equation: $-2\sqrt {3(\frac{23}{3}) - 7} - 11 = -19$ Multiply to simplify: $-2\sqrt {23 - 7} - 11 = -19$ Evaluate what is inside the radical: $-2\sqrt {16} - 11 = -19$ Evaluate the radical: $-2(4) - 11 = -19$ Multiply to simplify: $-8 - 11 = -19$ Add to simplify: $-19 = -19$

Work Step by Step

We need to isolate the radical, so we add $11$ to each side of the equation first: $-2\sqrt {3x - 7} = -8$ Divide both sides by $-2$ to isolate the radical: $\sqrt {3x - 7} = 4$ We need to get rid of the radical, so we square both sides of the equation: $3x - 7 = 4^{2}$ Evaluate the right side of the equation: $3x - 7 = 16$ Add $7$ to both sides of the equation to collect constants on the right side of the equation: $3x = 23$ Divide both sides by $3$ to solve for $x$: $x = \frac{23}{3}$ To check if our solution is correct, we plug it into the original equation: $-2\sqrt {3(\frac{23}{3}) - 7} - 11 = -19$ Multiply to simplify: $-2\sqrt {23 - 7} - 11 = -19$ Evaluate what is inside the radical: $-2\sqrt {16} - 11 = -19$ Evaluate the radical: $-2(4) - 11 = -19$ Multiply to simplify: $-8 - 11 = -19$ Add to simplify: $-19 = -19$
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