Question

Find an equation of the line. -5 10 Mac

Answer 1

Solution:

You want to find the equation for a line that passes through the two points: (0,3) and (-1,-1) First of all, remember what the equation of a line is Where: . m is the slope, and b is the y-intercept First, let's find what m is, the slope of the line The slope of a line is a measure of how fast the line "goes up" or "goes down". A large slope means the line goes up or down really fast (a very steep line). Small slopes means the line isn't very steep. A slope of zero means the line has no steepness at all; it is perfectly horizontal For lines like these, the slope is always defined as "the change in y over the change in x" or, 1n equation form ?n

So what we need now are the two points you gave that the line passes through. Let's call the first point you gave, (0,3), point #1, so the x and y numbers given will be called x1 and yi, Or. x1-0 and yi-3 Also, let's call the second point you gave. (-1,-1), point #2, so the x and y numbers here will be called x2 and y2. Or, x2--1 and уг--1 . Now, just plug the numbers into the formula for m above, like this -4 -1

m 4 o, we have the first piece to finding the equation of this line and we can fill it into y=mx+b like this: Now, what about b, the y-intercept? To find b, think about what your (x.y) points mean: (0,3). When x of the line is 0, y of the line must be 3. . (-1,-1). When x of the line is -1, y of the line must be1 Because you said the line passes through each one of these two points, right? want, the 4 is already set and x and y are just two "free variables" sitting there. We can plug anything we want in for x and y here, but we want the equation for the line that specfically passes through the two points (0,3) and (-1,-1).

So, why not plug in for x and y from one of our (x.y) points that we know the line passes through? This will allow us to solve for b for the particular line that passes through the two points you gave!. You can use either (x.y) point you want..the answer will be the same: (0.3). y nx+b or 3-4 x 0+b, or solving for b: b-3-(4) (-1-1). y-mx+b or -1 4 x -1+b, or solving for b: Seel In both cases we got the same value for b. And this completes our problem. The equsticn of the line that passes twough the points (0.3) and (-1,-1) 1S V-4x+3