Answer:
x = 9
Step-by-step explanation:
(7x + 8) + (5x +2) + (7x - 1) = 180
19x + 9 = 180
19x = 171
so first option
X = 9
Add like-terms and make it equal to the triangle sum theorem which is 180.
7x+8+7x-1+5x+2=180
19x+9=180
-9 -9
Subtract 9 from 9 and 180, then divide both sides by 19.
19x/19 = x
171/19 = 9
So therefore, x=9.
