Check the picture below.
notice chord QR is a diameter, thus the vertex at P has a right-angle by Thales theorem.
Well, in order to first determine the slope or y-intercept, you must put change the equation to this format: y=mx+b.
m=slope and b=y-interceptI
in order to do that, you must change this equation.
x+3y=9
-x -x
----------
3y=9-x
Then, rewrite it as:
3y=-x+9
_______
3 3
simplify to
y=-x/3 +9
Answer: (-4,5)
Step-by-step explanation:
Rotating 90 deg. counterclockwise maps (x,y) onto (-y,x), so (5,4) maps onto (-4,5).