Chapter 3 - Linear Systems - 3-2 Solving Systems Algebraically - Practice and Problem-Solving Exercises - Page 146: 12

y=4; x=20

We are told that x=8y-12. Because the expression x+12y=68 has two variables in it, we must make it in terms of one variable by substituting out a variable. Thus, we substitute 8y-12 in for x (because we know that x=8y-12) to obtain that 8y+12y-12=68. We solve to obtain that y equals 4. We plug y=4 into x=8y-12 to find that y equals 20.