algebra
posted by pawan .
The area of a rectangle remains unchanged when it is made 5cm shorter and 5cm wider or when it is made 2cm longer and 1cm narrower. Its area, in square cm, is:

LW = (L+5)*(W5)
LW = LW + 5W 5L 25
5L  5W = 25
(L +2)(W1) = L W
L + 2W = 2
5L +10W = 10
Combining equations 3 and 6,
5W = 35
W = 7
L = 2W2 = 12
Area = 84 cm^2