Let the present age of son be x years. So, present age of father be (35 - x) years.
According to question,
x(35 - x) = 150
⇒ 35x – x2 = 150
⇒ x2 – 35x +150 = 0
Therefore, the required representation in the form of quadratic equation be x2 – 35x + 150 = 0