Reflection of straight lines: ACT Math Practice Question

Try the following ACT math practice question that tests your understanding of reflection of straight lines in the coordinate plane.

Let $y=mx+b$ be the image when the line $x-3y+11=0$ is reflected across the $x$-axis. The value of $m+b$ is

1. $\quad -6$
2. $\quad -5$
3. $\quad -4$
4. $\quad -3$
5. $\quad -2$

Choice C

Video Explanation