SOLUTION: the measure of angle x is 9 degrees more than twice the measure of angle y. if angle x and angle y are supplementary angles, find the measure of angle x.

Algebra ->  Angles -> SOLUTION: the measure of angle x is 9 degrees more than twice the measure of angle y. if angle x and angle y are supplementary angles, find the measure of angle x.      Log On


   

Question 642474: the measure of angle x is 9 degrees more than twice the measure of angle y. if angle x and angle y are supplementary angles, find the measure of angle x.
Answer by Century(7) About Me  (Show Source):
You can put this solution on YOUR website!
The measure of angle x is 9 degrees more than twice the measure of angle y.
The above sentence gives us the equation x=2y%2B9
If angle x and angle y are supplementary angles, find the measure of angle x.
This sentence gives the equation x%2By=180 because supplementary angles are two angles whose measures add to 180 degrees.
So this problem gives the following system of equations, which can be solved by substitution
x=2y%2B9
x%2By=180
Since we know that x=2y%2B9, 2y%2B9 can be substituted into the 2nd equation for x to give 2y%2B9%2By=180
Now we have 1 equation with 1 variable which can be rewritten as 3y%2B9=180
or subtracting 9 from both sides we have 3y=171
dividing both sides by 3 gives y=57
Therefore angle y is 57 degrees and angle x equals 180-57 or 123 degrees.