SOLUTION: Find a if the point (3,a) is on the line that passes through (-2,7) and (5,-3).

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Question 771914: Find a if the point (3,a) is on the line that passes through (-2,7) and (5,-3).
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
first find equation of a line that passes through (-2,7) and (5,-3)
Solved by pluggable solver: Find the equation of line going through points
hahaWe are trying to find equation of form y=ax+b, where a is slope, and b is intercept, which passes through points (x1, y1) = (-2, 7) and (x2, y2) = (5, -3).
Slope a is .
Intercept is found from equation a%2Ax%5B1%5D%2Bb+=+y%5B1%5D, or -1.42857142857143%2A-2+%2Bb+=+4.14285714285714. From that,
intercept b is b=y%5B1%5D-a%2Ax%5B1%5D, or b=7--1.42857142857143%2A-2+=+4.14285714285714.

y=(-1.42857142857143)x + (4.14285714285714)

Your graph:




y=-1.43x+%2B+4.14
if the point (3,a), means x=3 and y=a, plug it in equation above
a=-1.43%2A3+%2B+4.14
a=-4.29+%2B+4.14
a=-0.15