Answer:
60 degrees
Explanation:
All angles of a triangle will add up to equal 180 degrees.
Set up an equation to solve for x:
9x - 3 + 50 + 9x + 7 = 180
Combine like terms
18x + 47 + 7 = 180
18x + 54 = 180
Subtract 54 from both sides
18x = 126
Divide both sides by 18
x = 7
Now plug in 7 for x in the expression for angle A:
9(7) - 3
63 - 3
60
Check work:
60 + 50 + 9(7) + 7 = 180
110 + 63 + 7 = 180
173 + 7 = 180
180 = 180
Correct