Precalculus: Mathematics for Calculus, 7th Edition

Published by Brooks Cole
ISBN 10: 1305071751
ISBN 13: 978-1-30507-175-9

Chapter 10 - Section 10.2 - Systems of Linear Equations in Several Variables - 10.2 Exercises - Page 697: 37

Answer

(1, -1, 1, 2)

Work Step by Step

The question asks to find the solution to the system of equations. Given: 1. $x + z + 2w = 6$ 2. $y - 2z = -3$ 3. $x + 2y - z = -2$ 4. $2x + y + 3z - 2w = 0$ Substitute $ y = -3 + 2z $ (from equation 2) 1. $x + z + 2w = 6$ 3. $x + 2(-3 + 2z) - z = -2$ 4. $2x + (-3 + 2z) + 3z - 2w = 0$ 1. $x + z + 2w = 6$ 3. $x + 3z = 4$ 4. $2x + 5z - 2w = 3$ Substitute $x = 4 - 3z$ (from equation 3) 1. $(4 - 3z) + z + 2w = 6$ 4. $2(4-3z) + 5z - 2w = 3$ $-2z + 2w = 2$ + ($-z - 2w = -5$) $-3z = -3$ $z = 1$ Solve for other variables $-2(1) + 2w = 2$ $2w = 4$ $w = 2$ $x = 4-3(1)$ $x = 1$ $y = -3 + 2(1)$ $y = -1$ Solution: (1, -1, 1, 2)
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