Chapter 3 - Linear Systems - 3-2 Solving Systems Algebraically - Practice and Problem-Solving Exercises - Page 146: 10

x=.5; y=2.5

We are told that y=5x. Because the expression 4x+2y has two variables in it, we must make it in terms of one variable by substituting out a variable. Thus, we substitute 5x for y (because we know that y=5x) to obtain 4x + 10x =7. We solve to obtain that x equals .5. We plug x=.5 into y=5x to find that y equals 2.5.