Question 363034
Are the points (-1,8), (1,2), and (4,-7) on the same line?  Explain your reasoning
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find the slope of the line passing through (-1,8) (1,2)
m=2-8/1-(-1)
=-6/2
=-3
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form an equation using (-1,8). If the other two points satisfy the equation then all points are collinear.
y-8=-3(x-(-1)
y-8=-3x-3
y=-3x-3+8
y=-3x+5
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point 1,2
2=-3(1)+5
2=-3+5
2=2 ( TRUE)
point (4,-7)
-7=-3*4+5
-7=-12+5
-7=-7 (TRUE)
so the lines are collinear
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m.ananth@hotmail.ca