In the Figure below is shown the graph of this function. We have the following function:
The 
occurs when 
, so:
Therefore, the is the given by the point:
From the figure we have three 
:
So, the occur when 
. Thus, proving this:
Alrighty, so, without the picture and the clues given I'm going to assume the image you have looks like two angles coming from the middle of a straight line. A straight line is equal to 180 degrees. 180 degrees minus 168 degrees equals 12.
11 is 110 for x and y
12 is 90 degrees for x and y
13 is also 90 degrees for x and y
To form a linear pair means that when added, they equal 180 degrees.
but if they have equal measures....180/2 = 90...then they would both equal 90 degrees.....and 90 degrees is a right angle.
So ABC and CBD are both right angles
