# coordinate geometry

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#1
the points A and B have coordinates (-4,6) and (2,8) respectively. A line P is drawn through b perpendicular to AB meet the y-axis qt the point C.
a) Find an equation of the line p
b) determine the coordinates of C

HELP!!! dying here!!!
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5 years ago
#2
(Original post by dancing doughnut)
the points A and B have coordinates (-4,6) and (2,8) respectively. A line P is drawn through b perpendicular to AB meet the y-axis qt the point C.
a) Find an equation of the line p
b) determine the coordinates of C

HELP!!! dying here
First find the equation of AB
Then use the gradient of ab to find the equation of P (perpedicular line so take the negative reciprocal of the gradient of AB (basically -1/(gradient of AB) )
Subsitute in the co ordinates of b into y=mx+c (obviously you would have found the gradient) and find the value of c to find the total equation of the line P

To find point C, you have to substitue it's co ordinates into the equation of P
When it crosses the y-axis, x=0, so use this co ordinate to find the y co ordinate by substituting it into thr equation of P as I said

This should work
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