00:01
All right, so the first thing we need to do is calculate our slope.
00:05
The formula for a slope for this line would be y2 minus y1 over x2 minus x1.
00:12
All right, and you need to pick two points on your graph.
00:16
So the points that i picked were, i can write them over here, 5b and 10b negative b.
00:29
So i'm going to plug these two points into my formula to calculate my slope.
00:34
So y2 in this case is going to be negative b, right? that's our y2.
00:41
So negative b minus y1 is b.
00:45
So negative b minus me divided by x2.
00:49
X2 is 10b minus 5b minus that x1.
00:55
All right.
00:55
B minus negative b minus b is a negative 2b 10b minus 5 b is a 5b b divided by b is 1 so these are going to cancel out so we have a slope is negative 2 over 5 all right now the other problem or the other point that it gave us on the graph was the y intercept in the problem and it tells us the y intercept is 0 -3.
01:29
So if ever you have the slope and the y intercept, you can write your equation in point or slope intercept form.
01:36
And so we could write y equals our slope negative 2 over 5x plus 3.
01:43
That's just the slope intercept form of an equation.
01:46
You can do that if you have the slope and the y intercept, in which case we have both.
01:51
So this is the equation of the line.
01:53
Now it doesn't just ask us for the equation of the line, right? it wants to know what point c is.
01:59
In order for us to know point c, we need to solve for b.
02:05
So we need to plug in a plot point into our equation and solve for b...