Answer:
x = 9
The angles: 71, 62, and 47
Explanation:
The total of 3 angles of a triangles equals 180 degrees
so (7x + 8) + (7x - 1) + (5x + 2) = 180
7x + 8 + 7x - 1 + 5x + 2 = 180
19x + 9 = 180
19x = 171
x = 9
so
7x + 8 = 7(9) + 8 = 71
7x - 1 = 7(9) - 1 = 62
5x + 2 = 5(9) + 2 = 47