Question

How do you find the missing number of a perfect square trinomial? 25x^2 - 60x + ___

Answer 1

Answer:

  36

Step-by-step explanation:

Compare what you have to the square ...

  (a +b)^2 = a^2 +2ab +b^2

Your "a" is √(25x^2) = 5x

Your "2ab" is -60x. Since you know "a", you can find "b".

  2ab = -60x

  2(5x)b = -60x . . . . . . . substitute for "a"

  b = -60x/(10x) = -6

Then the missing term is b^2 = (-6)^2 = 36.

Your trinomial is ...

  25x^2 -60x +36