I am lost it says to factor completely. Remember to look first for a common factor and to check by multiplying. If a polynomial is prime, state this.
20x^2 + 100x + 125

Question

I am lost it says to factor completely. Remember to look first for a common factor and to check by multiplying. If a polynomial is prime, state this.
      20x^2 + 100x + 125

anonymous · Answer

20x^2 + 100x + 125

5(2x + 5)(2x + 5)

5(2x + 5)^2

anonymous · Answer

what was the common factor ? and how do i go about looking for it?

anonymous · Answer

how do i go about checking it?

asnaseer · Answer

you might find this site helpful: http://www.mathsisfun.com/algebra/factoring-quadratics.html

phi · Answer

You can check it by multiplying it back out to get the original expression. It is good practice: (2x+5)*(2x+5)= 2x*2x+2x*5+5*2x+5*5 (using FOIL) you can finish it off... also, you can user wolfram, http://www.wolframalpha.com/input/?i=++++factor++20x%5E2+%2B+100x+%2B+125

anonymous · Answer

@phi using wolframalpha should never be a solution.

anonymous · Answer

First expand each part to look for common factors as the question states:
$$2 * 2 * 5 * X^{2}  + 2*2*5*5*x + 5*5*5$$

Then you can solve.