Suppose the slope of a straight line L is -3/4 and P is a given point on L. If Q is a point on L lying 2 units to the right of P, then Q is situated 3/2 units below P.
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The line L has an equation y = -¾ x + c. The value of c doesn't matter for this question, so let c = 0.
Hence, if P is the point (p, q) and Q is the point (s, t),
q = -¾p, and t = -¾s,
But Q is 2 units to the right of P, therefore its x-coordinate = (p + 2)
So in the equation t = -¾s, we can substitute (p + 2) for s, giving
t = -¾(p + 2)
. = -¾p - ¾ (2)
and since q = -¾p, then
t = q - (3/2)
So the y-coordinate of Q is (3/2) units below the y-coordinate of P.
Hence, if P is the point (p, q) and Q is the point (s, t),
q = -¾p, and t = -¾s,
But Q is 2 units to the right of P, therefore its x-coordinate = (p + 2)
So in the equation t = -¾s, we can substitute (p + 2) for s, giving
t = -¾(p + 2)
. = -¾p - ¾ (2)
and since q = -¾p, then
t = q - (3/2)
So the y-coordinate of Q is (3/2) units below the y-coordinate of P.
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slope is y2-y1/x2-x1=-3/2.since the difference of y coordinates gives the height of line.
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- 3/4 = (y2-y1) / (x2-x1)
if x2-x1 = 2
then y2-y1 =
-3/4 = (y2-y1) /2
- 6/4 = y2-y1 = -3/2
indeed the rise = 3/2
if x2-x1 = 2
then y2-y1 =
-3/4 = (y2-y1) /2
- 6/4 = y2-y1 = -3/2
indeed the rise = 3/2