Let daughter be x years old. Then, Shyam is (x + 28) years old.
So,
x(x + 28) = 204
=> x² + 28x = 204
=> x² + 28x - 204 = 0
=> x² - 6x + 34x - 204 = 0
=> x(x-6) + 34(x-6)
=> (x - 6) (x + 34) = 0
=> x - 6 = 0 or x + 34 = 0
=> x = 6 or x = -34
Since any age cannot be negative, daughter's age is 6 years old.
