Plz help.Equation of the line through points (-2,0) and (1,-3)?

Question

i need more specifically how to get the y-intercept, thx for helping.

Answer 1

ok first you need to find the slope. use the equation (y2-y1)/(x2-x1) or (-3-0)/(1--2) which comes to a slope of -3/3 or -1. now you take the formula for a like y=mx+b. you just plug in what you know. take on of the points and plug them in for y and x and plug -1 in for m which is the slope. and solve for b. im going to use the first point. 0=(-1)(1)+b. which makes b=1. now you plug the slope and b back into the formula to the line. y=-1x+1. if you want the the y intercept, you make x=0. so y=-1(0)+1. so y=1 which is your y intercept

Answer 2

slope = (-3 - 0) / (1 - (-2) ) = -3 / 3 = -1

equation (using point slope formula for first point

(y-0) = -1 (x- (-2))

y = -1(x+2)

put x = 0 to find y intercept

y = -1(0+2) = -1(2) = -2  <---ANSWER

rewrite in slope-intercept if needed

y = -1x -2

y=-x-2

Answer 3

y=-x-2

so, y-intercept=-2

Answer 4

the equation for the line is

y=mx+b

so figure out what you have...

you have a y and an x (which you can get from either point)... but no m (slope) or b (y-intercept)

to find the slope, use the equation

(y2-y1)/(x2-x1)

and you get

(0--3)/(-2-1)

which equals

3/-3  or -1

Now take one of the points (-2,0) and the m or slope which is -1 and plug it into the equation to find b.

y=mx+b

0=(-1)(-2)+b

0=2+b

so.....

b= -2

Hope this helped... :-)

Answer 5

You need to use 2 line equations to solve this.

The regular line equation is:

y = mx + b

where m = slope of the line, and b = the y intercept.  So you are solving for b to get the y intercept.  You'll need to plug in the other 3 values to solve for it.

Since you do not have the slope, you need to use the slope equation to solve for it, which requires 2 points (x and y values) which you have.  That equation is:

y1 - y2 = m(x1 - x2)

Plug in the values of your 2 points to solve for m

0-(-3) = m(-2 - 1)

3=m(-3)

m=3/(-3)

m=(-1)

plug that into the first equation, along with either of the 2 x and y values:

y = mx + b

-3=(-1)*1 +b

-3=(-1) + b

b=(-3) +1

b=(-2)

Answer 6

The slope of the line is the change in y divided by the change in x:

Slope = [0 - (-3)] / [(-2) - 1)]

= 3 / -3

= -1

The line falls one unit of y for every unit increase in x.

As the line falls from (-2, 0), the next point will be (-1, -1) and the following will be (0, -2) which is the y-intercept.

This can be calculated by adding 2 to the x value to get to the y-axis and applying the change in x (2) times the slope (-1) to get a change in y of -2.

The equation for the line is:

y = -x - 2