Explain why the polynomial 144x2 - 200x + 81 is not a perfect square.

The square root of 144x^2 = 12 x

and square root of + 81 = 9 or - 9

if this polynomial were a perfect square then its factors would be

(12x - 9) (12x - 9)

but its not a perfect squre because (12x - 9) (12x - 9) = 144x^2 - 216x + 81.