Question 444904
By definition, supplementary angles add up to 180.  So we have two angles. Let's call them A and B. Now we are given an angle. Its measure is 2B - 60. Let's call this A.  Then by definition, 2B - 60 + B = 180.  Solve for B.  Then:
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3B = 240,  B = 80.
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Since we know B = 80 and we have an expression for A,  A= 2B-60, then:
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A = 2(80) - 60 
A= 100

So our two angles are 100 and 80, which obviously add up to 180.