## Precalculus (6th Edition) Blitzer

There are two equations that we can use: y=3x and x+y=4. Since y=3x is already simplified in which one variable is isolated from the rest we can substitute this equation into x+y=4. x+y=4 x+3x=4 Solve for x. First combine like-terms. 4x=4 Then divide by four on both sides. $\frac{4x}{4}$=$\frac{4}{4}$ x=1 Substitute x=1 into y=3x to solve for y. y=3(1) y=3 The ordered pair would then be (1,3)