Answer:
Area of a rectangle= lenght× width
Dimensions of 1st rectangle: L,W
Dimensions of 2nd rectangle: L+10; W+4
Hence,
LW = 480__________(1)
(L-10)(W+4) = 480_______(2)
LW = LW+4L - 10W - 40
4L = 10W +40
2L = 5W + 20
L = (5/2)W + 10_________(3)
But LW = 480 (from equation one)
So, W = 480/L
substitute as= 480/L into equation (3)
L = (5/2)(480/L)+10
L = 1200/L + 10
L^2 - 10L - 1200 = 0
factorising.
we're have,
(L-40)(L+30) = 0
therefore, since L can't be negative , L = 40
L = 40 cm (length)
Then 480/L = W = 120 cm (width)