Question

If the graph of the line x-2y=-1 in the xy plane is reflected across the x axis, which of the following is an equation of the resulting reflection?
x-2y=-1
x+2y=-1
x-2y=1
x+2y=1
2x+y=-2

Show work!

Answer 1

@SithsAndGiggles

Answer 2

@satellite73

Answer 3

@Directrix lol.

Answer 4

For y=f(x), the equation y=-f(x) is a reflection over the x-axis. That is, it takes every y coordinate and multiplies it by -1.

So if you just solve the equation for y=mx+b, then the reflection across the x-axis is the line y=-(mx+b).

Then you just need to put it back into standard form to make it fit your answer choices.