Explanation:
Given P = 42 cm and Area = 68cm^2
So we apply the above values to its formula to find length and breadth
P = 2L + 2w = 42cm
L + w = 21cm (dividing the above statement by 2)
(21-w)w = 68cm^2
w^2 - 21w + 68 = 0 (moving variables and framing equations)
(w - 17)(w-4) = 0 , w = 4cm,17cm (calculating the values by using the equation)
Rectangle is 4cm by 17cm