Question 260398: Find the equation of the line through (2,a) and (9,b).
y=___________
Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website! Find the equation of the line through (2,a) and (9,b).
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|x y 1|
|2 a 1| = 0
|9 b 1|
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x(a-b) - y(2-9) + 2b-9a = 0
xa-xb + 7y + 2b-9a = 0
7y = (b-a)x + 9a - 2b
y = ((b-a)/7)*x + 9a/7 - 2b/7
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The usual method:
m = (b-a)/7
Use y=mx+B and either point to find B the y-intercept
a = 2(b-a)/7 + B
B = (7a - 2(b-a))/7
y = mx + B
y = ((b-a)/7)*x + (7a - 2(b-a))/7
y = ((b-a)/7)*x + (9a - 2b)/7 same answer
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