Question 325626
x^2=20x
=> x^2 - 20x = 0
To make the quadratic equation a complete square, the determinant should be zero.
Hence, if the required equation is x^2 - 20x +c = 0
Determinant = (-20)^2 - 4 x 1 x c = 0
=> 400 = 4c
=> c = 400/4 = 100.
Answer: d