Back to Parallel lines are taken to parallel lines — Problem 3 · Task Set 21

Exercises: Rigid Motions Preserve Parallelism

Work through each section in order. Two lines are parallel when they have the same slope (or are both vertical). For each transformation, find the slopes of the image lines and check whether they stay equal.

Grade 8·20 problems·~30 min·Common Core Math - Grade 8·standard·8-g-a-1c

Work through problems with immediate feedback

Fluency Practice

The parallel lines $y = 3x + 2$ and $y = 3x - 4$ are reflected over the y-axis. What are the slopes of the image lines?

Both $-3$ , so the image lines are parallel

Both $3$ , unchanged

One is $3$ and the other is $-3$ , so they are not parallel

Both $\frac{1}{3}$