SOLUTION: A line passes through (-2,4) and (3,9). Could you please show me how to write an equation for the line in slope-intercept form step-by-step? Thank you :)

Algebra ->  Equations -> SOLUTION: A line passes through (-2,4) and (3,9). Could you please show me how to write an equation for the line in slope-intercept form step-by-step? Thank you :)      Log On


   

Question 433090: A line passes through (-2,4) and (3,9). Could you please show me how to write an equation for the line in slope-intercept form step-by-step?
Thank you :)
Found 2 solutions by Alan3354, josmiceli:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Here's an example.
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Find the equation given 2 points:
Points (3,7) and (6,1)
Find m, the slope
m = diffy/diffx = (6-3)/(1-7) = 3/(-6)
m = -1/2
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Use y = mx + b and either point to find b, the y-intercept
7 = (-1/2)*3 + b
b = 8.5 or 17/2
--> y = (-1/2)x + 17/2 in slope-intercept form
x + 2y = 17 in standard form
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email via the thank you note for help, or to check your work.

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
If the given points are (x1,y1) and (x2,y2), then
the formula to use is:
(y - y1) / (x - x1) = (y2 - y1) / (x2 - x1)
Applying this to your points,
(-2,4), (3,9)
+%28y+-+4%29+%2F+%28x+-+%28-2%29%29+=+%289+-+4%29+%2F+%283+-+%28-2%29%29+
+%28y+-+4%29+%2F+%28x+%2B+2%29+=+5+%2F+5+
+%28y+-+4%29+%2F+%28x+%2B+2%29+=+1+
+y+-+4+=+x+%2B+2+
+y+=+x+%2B+6+
Check to see if it goes through the points
(-2,4)
+4+=+-2+%2B+6+
+4+=+4+
OK
(3,9)
+9+=+3+%2B+6+
+9+=+9+
OK