<PRE><B>Question 10974</B>
A/R(representing the unknown):
4x = Angle A
x = Angle B
x-20 = Angle c

E(Equation):  4x + x + x - 20=180

S(Solution): 

4x + x + 20 - x = 180

Add 4x + x - x = 4x

Then, transposed -20 to the right side showing us

180 - 20 = 160

 4x = 160


Now, Divide 4 to both sides like this:

4x/4 = 160/4


The Answer is x = 40
C(Checking): 4(40) = 160 =Angle A
             x = 40 = Angle B
             20 - 40 = -20

4(40) + 40 + 20 - 40 = 180
160 + 60 - 40 =180
220 - 40 = 180
180 = 180
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