Answer:
x = 19
ABC = 48°.
Step-by-step explanation:
(7x - 1) + (3x - 9) = 180.
(7x - 1 + 1) + (3x - 9) = 180 + 1
7x + 3x - 9 = 10x - 9
10x - 9 = 181
10x - 9 + 9 = 181 + 9
10x = 190
10x/10 = 190/10
ABC = (3x - 9)
3 x 19 = 57
57 - 9 = 48
