SOLUTION: I cannot find a place that explains how to do this problem,any help would be appreciated. Angles A and B are supplementary angles because their sum is 180 degrees. The measure o

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Question 22620: I cannot find a place that explains how to do this problem,any help would be appreciated.
Angles A and B are supplementary angles because their sum is 180 degrees. The measure of angle A is ten less than 4 times the measure of angle B. Find the measure of angle B?
1. 45 degrees
2. 38 degrees
3. 142 degrees
4. 36 degrees

Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Start with A + B = 180 degrees (A means...the measure of angle A)
A = 4B-10 "The measure of angle A is (=) 4 times the measure of angle B (4B) less 10 degrees (-10)". Substitute this equation for A into the above equation for A + B = 180.
(4B-10) + B = 180 Simplify and solve for B
5B - 10 = 180 Add 10 to both sides.
5B = 190 Divide both sides by 5.
B = 38 degrees.
Check:
A = 4(38)-10 = 152 - 10 = 142 degrees.
A + B = 142 + 38 = 180 degrees.