SOLUTION: Hi I need help with equation of lines so how do I do M= -3 b=1 when my formulas are y = mx+b and m=y2-y1

Algebra ->  Points-lines-and-rays -> SOLUTION: Hi I need help with equation of lines so how do I do M= -3 b=1 when my formulas are y = mx+b and m=y2-y1       Log On


   

Question 1017301: Hi I need help with equation of lines so how do I do
M= -3 b=1 when my formulas are y = mx+b and m=y2-y1
X2-X1
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+y+=+m%2Ax+%2B+b+
+m+=+-3+
+b+=+1+
Your equation looks like:
+y+=+-3x+%2B+1+
----------------
Then you have the point-slope formula:
+m+=+%28+y%5B2%5D+-+y%5B1%5D+%29+%2F+%28+x%5B2%5D+-+x%5B1%5D+%29+
-----------------------------
This formula gives you the slope, +m+,
when you plug in 2 points on the line:
( x1, y1 ) and
( x2, y2 )
---------------
For the given line, your points could be:
( 0, 1 ) and ( 1, -2 )
See if the formula works:
+m+=+%28+y%5B2%5D+-+y%5B1%5D+%29+%2F+%28+x%5B2%5D+-+x%5B1%5D+%29+
+m+=+%28+-2+-+1+%29+%2F+%28+1+-+0+%29+
+m+=+-3%2F+1+
+-3+=+-3+
OK