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 146: 16

Answer

The solution to this system of equations is $r = -6$ and $t = -9$.

Work Step by Step

In the first equation, we already have an expression for $t$ that we can substitute into the second equation to find $r$. Let us do the substitution: $5r - 4(2r + 3) = 6$ Use distributive property to get rid of the parentheses: $5r - 8r - 12 = 6$ Add $12$ to both sides to isolate constants to the right side of the equation: $5r - 8r = 18$ Add like terms on the left side to simplify: $-3r = 18$ Divide each side by $-3$ to solve for $r$: $r = -6$ Now that we have a value for $r$, we can substitute it into the first equation to solve for $t$: $t = 2(-6) + 3$ $t = -12 + 3$ $t = -9$ The solution to this system of equations is $r = -6$ and $t = -9$. Let us substitute these values into the second equation to see if the equation holds true: $5(-6) - 4(-9) = 6$ $-30 + 36 = 6$ $6 = 6$ This statement is true; therefore, the solution is correct.
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