SOLUTION: please help me solve this What equation of the line passes through the points with coordinates (-2,1) and (1,2)

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: please help me solve this What equation of the line passes through the points with coordinates (-2,1) and (1,2)      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 374699: please help me solve this
What equation of the line passes through the points with coordinates (-2,1) and (1,2)
Answer by sophxmai(62) About Me  (Show Source):
You can put this solution on YOUR website!
Ok, so your coordinates are (-2,1) and (1,2).
The equation of the line is y=mx+b

First, find the slope, m.
m=%28y2-y1%29%2F%28x2-x1%29
m=%28%282%29-%281%29%29%2F%28%281%29-%28-2%29%29
m=1%2F3

Now, you have y=%281%2F3%29x%2Bb
Now, plug in one of the coordinates in for x and y, and then solve for b (the y-intercept).

y=%281%2F3%29x%2Bb
%282%29=%281%2F3%29%281%29%2Bb
2=%281%2F3%29%2Bb
2-%281%2F3%29=b
1%282%2F3%29=b
%285%2F3%29=b

And now you have y=%281%2F3%29x%2B%285%2F3%29

To check to see if this is correct, sub in x or y of one coordinate and see if you get the other value (sub in x, get the correct y, or sub in y and get the correct x).
(-2,1)
y=%281%2F3%29x%2B%285%2F3%29
y=%281%2F3%29%28-2%29%2B%285%2F3%29
y=%28-2%2F3%29%2B%285%2F3%29
y=%283%2F3%29
y=1