Chapter 5 - Linear Functions - 5-6 Parallel and Perpendicular Lines - Practice and Problem-Solving Exercises - Page 334: 7

$y=3x$

Parallel lines have the same slope so the two equations would have the same slope ($3$). Use the point($1,3)$ and the slope and plug them into $y=mx+b$: $y=mx+b$ $3=3(1)+b$ -distribute- $3=3+b$ -subtract 3 from both sides- $0=b$ The $y$-intercept is $0$ and the slope is $3$ so $y=3x$.