Explanation:
The perimeter is the sum of all sides.
AB+AC+CB=75
(2x-9) + (2x+3) + (3x+4) = 75
Combine like terms:
(2x+2x+3x) + (-9+3+4) = 75
7x - 2 = 75
7x = 77
x=11
Replace 'x' with '11' in the above equations to find that:
AB = 2(11) - 9 = 22 - 9 = 13 m
AC = 2(11) + 3 = 22 + 3 = 25 m
CB = 3(11) + 4 = 33 + 4 = 37 m
13 + 25 + 37 = 75 m