Without graphing, determine which of the following equations represents lines that are parallel to each other. Which are perpendicular? Show how you know. Homework Help ✎
–3x + y = 5
–5x + y = 3
x + 5y = –15
–15x + 5y = –25
Put each equation into slope-intercept form
(y = mx + b, where m is the slope and b is the y-intercept). That means to solve for y.
Compare the slopes. If they are equal then they are parallel.
If they are the negative reciprocal of each other then they are perpendicular,