Question

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

Answer 1

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.