SOLUTION: How do I write an equation pASSING THROUGH TWO GIVEN POINTS IN SLOPE-INTERCEPT FORM?

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Question 392234: How do I write an equation pASSING THROUGH TWO GIVEN POINTS IN SLOPE-INTERCEPT FORM?
Found 2 solutions by ewatrrr, MathLover1:
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!

Hi
I.Use the point-slope formula, m+=%28y%5B2%5D+-+y%5B1%5D%29%2F%28x%5B2%5D+-+x%5B1%5D%29 to find slope
II. then use Using the standard slope-intercept form for an equation of a line
y = mx + b where m is the slope and b the y-intercept to start the process
by substituting slope value found for m
III. use on the the ordered pairs to solve for b
IV. substitute that value found for b in the equation
For ex: Points (1,1)(5,6) m = 5/4
y = (5/4)x + b
1 = (5/4) + b
(-1/4) = b therefore: y = (4/5)x -1/4


Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!
example:
Find the equation of the line that passes through the points (–2, 4) and (1, 2).
Well, if I have two points on a straight line, I can always find the slope; that's what the slope formula is for.
slope+m+=+-2%2F3
Now I have the slope and two points. I know I can find the equation (by
solving first for "b") if I have a point and the slope. So I need to pick
one of the points (it doesn't matter which one), and use it to solve for b.
Using the point (–2, 4), I get:
y+=+mx+%2B+b
y+=+-%282%2F3%29%28-2%29+%2B+b

4+=+4%2F3+%2B+b
4+%96+4%2F3+=+b
12%2F3+%96+4%2F3+=+b
+b+=+8%2F3
...so

y+=+-%282%2F3%29x+%2B+8%2F3

On the other hand, if I use the point (1, 2), I get:
y+=+mx+%2B+b
2+=+-%282%2F3%29%281%29+%2B+b

2+=+-%282%2F3%29+%2B+b

+2+%2B+2%2F3+=+b
+6%2F3+%2B+2%2F3+=+b
+b+=+8%2F3
So it doesn%27t+matter which point I choose. Either way, the answer is the same:
y+=+-%282%2F3%29x+%2B+8%2F3

As you can see, once you have the slope, it doesn't matter which point you use in order to find the line equation. The answer will work out the same either way.
in general, we have
the points (x1, y1) and (x2, y2)

slope m+=+%28y1-y2%29%2F%28x1-x2%29

y+=+mx+%2B+b............