Answer:
The answers to your questions are:
a) x = 14
b) x = 25
Explanation:
a) (7x -1) + (6x -1) = 180
7x -1 + 6x -1 = 180
7x + 6x = 180 + 1 +1
13x = 182
x = 182/13
x = 14
b) 5x +4 = 8x - 71
8x - 71 = 5x + 4
8x - 5x = 71 + 4
3 x = 75
x = 75 / 3
x = 25