00:01
Part a wants us to find the equation of line m.
00:03
So line m is this line right here.
00:06
So i'm going to pick two points on the line.
00:09
Here i have a negative 8, 0.
00:11
And here i have 0, 4.
00:14
And we can use those two points to find the equation on the line.
00:18
So we said we had negative 8, 0 and 0, 4.
00:24
To find the slope between two points, we have m equals y2 minus y1 over x2 minus x1.
00:34
And now we can substitute.
00:37
And i get 0 minus 4 over negative 8 minus 0.
00:45
0 minus 4 is negative 4.
00:47
Negative 8 minus 0 is negative 8.
00:50
So i get negative 4 over negative 8, which reduces to 1 half.
00:55
This is the slope of that line.
00:58
So we're going to put this in slope -intercept form.
01:02
Which says y equals mx plus b, where m is the slope and b is the y -intercept.
01:10
So we get y equals 1 half, because we just figured that out that that was the slope, x plus b, which is the y -intercept, which is 4, and we have that right on the graph it was given to us.
01:25
So the slope of line m is y equals 1 half x plus 4.
01:30
Part b is asking us for the equation of line d.
01:38
Line d is this line right here.
01:40
So again, we're going to pick two points on the line.
01:43
But when we try to do that, we see we actually don't have two points on the line.
01:47
I actually just have this one at 6, 0.
01:51
So that's not going to work.
01:53
But what we do have here at b is that 90 degree angle...