Algebra: A Combined Approach (4th Edition)

Published by Pearson
ISBN 10: 0321726391
ISBN 13: 978-0-32172-639-1

Chapter 4 - Review - Page 329: 37

Answer

$$x=3$$ $$y=2$$

Work Step by Step

Equation 1: $x + 4y = 11$ Equation 2: $5x - 9y = -3$ Solve the system using substitution method. Using equation 1, subtract $4y$ from both sides: $$x + 4y -4y= 11-4y$$ $$x = 11-4y$$ Substitute this equation to equation 2: $$5(11-4y)- 9y = -3$$ $$55-20y- 9y = -3$$ $$55-29y=-3$$ Subtract $55$ from both sides: $$55-55-29y=-3-55$$ $$-29y=-58$$ Divide both sides by $-29$ $$\frac{-29y}{-29}=\frac{-58}{-29}$$ $$y=2$$ Substitute this value of $y$ to equation 1: $$x+4(2)=11$$ $$x+8=11$$ Subtract $8$ from both sides: $$x+8-8=11-8$$ $$x=3$$ Use equation 2 to check: $$5(3)-9(2)=-3$$ $$15-18=-3$$ $$-3=-3$$
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