Sam decides to build a square garden. If the area of the garden is 25x2 + 30x + 9 square feet, what is the length of one side of the garden?

A) (3x + 5) feet

B) (3x - 5) feet

C) (5x + 3) feet

D) (5x - 3) feet

The correct answer is C. (5x+3) feet, and here is how I got it.

This is the equation you need to use:

(a+b) ^2 = (a+b) (a+b)

So, let us plug in 5x and 3 here:

(5x+3) ^2 = (5x+3) (5x+3) = 25x^2 + 15x + 15x + 9 = 25x^2 + 30x + 9 which is the area of the garden.