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 - Chapter Review Exercises - Page 670: 67

Answer

$x = 16$ To check if our solution is correct, we substitute it back into the original equation: $-3\sqrt {2(16) - 7} + 14 = -1$ Multiply factors within the radical: $-3\sqrt {32 - 7} + 14 = -1$ Simplify the radical: $-3\sqrt {25} + 14 = -1$ Evaluate the square root: $-3(5) + 14 = -1$ Multiply first: $-15 + 14 = -1$ Add to simplify: $-1 = -1$ The two sides are equal; therefore, the solution is correct.

Work Step by Step

We want to isolate the radical on the left side of the equation, so first, we subtract $14$ to each side of the equation: $-3\sqrt {2x - 7} = -15$ Divide both sides by $-3$ to isolate the radical: $\sqrt {2x - 7} = 5$ Square both sides of the equation: $2x - 7 = 5^2$ Evaluate the right side of the equation: $2x - 7 = 25$ Add $7$ to each side of the equation: $2x = 32$ Divide both sides of the equation by $2$: $x = 16$ To check if our solution is correct, we substitute it back into the original equation: $-3\sqrt {2(16) - 7} + 14 = -1$ Multiply factors within the radical: $-3\sqrt {32 - 7} + 14 = -1$ Simplify the radical: $-3\sqrt {25} + 14 = -1$ Evaluate the square root: $-3(5) + 14 = -1$ Multiply first: $-15 + 14 = -1$ Add to simplify: $-1 = -1$ The two sides are equal; therefore, the solution is correct.
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