Algebra 2 Common Core

Published by Prentice Hall
ISBN 10: 0133186024
ISBN 13: 978-0-13318-602-4

Chapter 3 - Linear Systems - 3-2 Solving Systems Algebraically - Practice and Problem-Solving Exercises - Page 147: 46

Answer

The solution to this system of equations is $(-1, -\frac{1}{2})$.

Work Step by Step

We can solve for $y$ in terms of $x$ in the second equation so that we can use this value for $y$ to substitute into the first equation. Let us solve for $y$ in the second equation: $8y = 4x$ Divide both sides by $8$ to solve for $y$: $y = \dfrac{4x}{8}$ Reduce the fraction by dividing both numerator and denominator by $4$: $y = \dfrac{x}{2}$ Now, we use this value for $y$ to substitute into the first equation: $7x + 2(\frac{x}{2}) = -8$ $7x + x = -8$ $8x = -8$ Divide both sides by $8$ to solve for $x$: $x = -1$ Now that we have a value for $x$, we can substitute it into the second equation to solve for $y$: $8y = 4(-1)$ $8y = -4$ Divide both sides by $8$ to solve for $y$: $y = -\dfrac{4}{8}$ Divide both numerator and denominator by $4$ to simplify the fraction: $y = -\dfrac{1}{2}$ The solution to this system of equations is $(-1, -\frac{1}{2})$.
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