Question 92914
Let the length of second side = x cm.
The first side is 40 cm shorter than twice the second side; hence its length = 
(2x - 40) cm.
The third side is 2 cm longer than the second side; hence its length = (x + 2) cm.


Perimeter = sum of lengths of all sides
70 = x + (2x - 40) + (x + 2)
4x - 38 = 70
4x = 70 + 38 = 108
x = 108/4 = 27


Ans: 
1st side is (2*27 - 40 =) 14 cm, 
2nd side is 27 cm and 
3rd side is (27 + 2 =) 29 cm.