00:01
So in this question, we're going to look for the equation of the line passing through the point negative 5 .3 that's perpendicular to our line x plus 5y minus 7 equals 0.
00:11
We're going to do this in point slope form and general form.
00:16
So how are we going to do this? well, i should start by figuring out the slope of the line that i've been given, x plus 5y minus 7 equals 0, right? so what am i going to do here? well, i'm going to put this in y equals four.
00:36
So let me solve for y.
00:38
I'll subtract the x and i'll add the seven.
00:42
So 5y equals negative x plus seven, and then i'll divide by five so that i have y equals negative one -fifth x plus seven -fifths, right? and so now, now, if i want to write the point slope form of this line, i know that i'm going to have a slope of what? well, i am perpendicular to the line, y equals negative one -fifth x plus seven -fifths.
01:17
To get the slope of my perpendicular line, i have to take the opposite reciprocal of the slope of the line that i've been given.
01:28
The line that i've been given has slope negative one fifth.
01:32
And so something perpendicular to that will have a slope of positive 5.
01:39
That is the opposite reciprocal of negative 1 fifth.
01:44
And so if i wish to write the equation of our line in point slope form, well, we're going to have y minus the y coordinate of our point.
01:55
We said we're passing through negative 5 .3, so y minus 3, that's my y coordinate, is equal to my slope 5 times the quantity of x minus my x coordinate...