Answer:
5x + 3
Step-by-step explanation:
We factor 25x^2 + 3x + 9.
25x^2 is a perfect square; 25x^2 = (5x)^2
9 is a perfect square; 9 = 3^2
This expression may be a perfect square trinomial.
25x^2 + 30x + 9 = (5x + 3)^2
We check the middle term: 2ab = 2 * 5 * 3 = 30
The coefficient, 30, is correct, so we are dealing with a perfect square trinomial.
length = 5x + 3
