Question

Determine if thr lines are parallel, perpendicular, or neither
x-y=4 and x+y=9

Answer 1

Perpendicular

Explanation:

Let's convert both equations to the format y=mx+b

x-y=4 --> y=x-4

x+y=9 --> y=-x+9

Now, if it's parrarel, they will be the same slope just differnet y-intercepts.

The slopes are clearly different as one is negative 1, the other positive 1. To find out if they are perpendicular, we must multiple the slopes and if that answer is -1, they are.

-1 * 1 = -1

Yes, they are perpendicular.

Find more about y=mx+b in the photo below. :)