Equation of a one straight line
The diagram below shows a triangle . The equation of is and the gradient of is . Find the coordinate of .
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
1 solution
Given that point P and the gradient of PR is 4/3, therefore
( y - y1 ) = m ( x - x1 )
y - 2 = 4/3 ( x - 0 )
3y - 6 = 4x
y = (4/3)x + 2
Also, we still know that the equation of QR is y = - 4x + 18, and the intersection point is Q, therefore
y = (4/3)x + 2 ------------ ( 1 )
y = - 4x + 18 ------------ ( 2 )
Let ( 1 ) = ( 2 )
(4/3)x + 2 = - 4x + 18
4x + 6 = -12x + 54
16x = 48
x = 3
Substitute x = 3 into ( 2 )
y = - 4( 3 ) + 18
y = - 12 + 18
y = 6
Therefore the Coordinate of Q is ( x, y ) = ( 3 , 6 )