Question 392057
(9x + 3) + (7x + 1)
9x + 3 + 7x + 1= 180
16x + 4= 180
16x + 4 - 4= 180 - 4
16x= 176
x= 11 
:
You've done the main part, just substitute 11 for x in the two original expressions
9(11) + 3 = 102 degrees
7(11) + 1 = 78 degrees
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totals to 180 degrees which is what it should do