Posted by **kim** on Wednesday, September 23, 2009 at 7:05pm.

find an equation of the line that passes through the points

(0,0),(-1,5)

and

(2,1),(0,-3)

- pre calculus -
**DrBob222**, Wednesday, September 23, 2009 at 7:37pm
The first one is

slope = y1-y2/x1-x2

slope = m = (0-5/0+1 = -5

y = mx + b

Then put in one of the points to calculate b.

5 = -5(-1) + b

5 = 5 + b

b = 0

So the line is

y= mx + b

y = -5x + 0 or y = -5x.

The other one is don the same way.

Check my work very carefully.

- pre calculus -
**kim**, Wednesday, September 23, 2009 at 7:43pm
is the other problem is

y=-3x+0

- pre calculus -
**jim**, Wednesday, September 23, 2009 at 7:43pm
The first pair is very very easy.

Remember that a line that passes through the origin must be of the form:

y = mx

since the intercept is zero. You are told that this line passes through the origin and that the point (-1, 5) satisfies the equation. You should be able to write the answerdown from there.

There are a couple of ways to do the second one. he two-point formula is

(y - y1) / (x - x1) = (y2 - y1) / (x2 -x1)

(y - 1) / (x - 2) = (-3 - 1) / (0 - 2)

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

multiply across by x - 2

y -1 = 2x - 4

and you should be close enough to finish from there.

## Answer this Question

## Related Questions

- Math 101 - Find the equation for each of the following items below: a. A line ...
- Pre-Calculus/Trigonometry - Help please Which of the following is the equation ...
- mat 101 - Equation for a line that passes through (6,26) and has a slope of 3 ...
- math - i have more than one question so if u no any of the answers please tell ...
- pre calculus - write the slope-intercept form of an equation for a line that ...
- Mathamatics - This question concerns the straight line that passes through the ...
- Math - This question concerns the straight line that passes through the points...
- pre-calculus - How do you write the standard form of the equation of the line ...
- pre-calculus - How do you write the standard form of the equation of the line ...
- math - (a)Given the points P(3,5),Q(8,10)and R(8,0),find the equation of a line ...