1. SET UP EQUATION
(15x+1)+(6x+5)+(4x-1)=180
2. SIMPLIFY
25x+5=180
3. SUBTRACT 5 ON BOTH SIDES
25x=175
4. DIVIDE 25 ON BOTH SIDES
x=7
5. PLUG IN 7 FOR EACH ANGLE
15(7)+1
6(7)+5
4(7)-1
6. SIMPLIFY
105+1
42+5
28-1
7. SOLVE
106
47
27
ANSWERS:
x=7
15x+1=106 degrees
6x+5=47 degrees
4x-1=27 degrees