Anonymous asked in Education & ReferenceHomework Help · 7 years ago

How to write functions in factored form?

5x2 + 20x + 15

(5x2 is 5 to the second power) idk how to do these help :(

1 Answer

  • Angela
    Lv 5
    7 years ago
    Favorite Answer

    5x^2 + 20x + 15

    First, factor out the 5

    5(x^2 +4x +3)

    Now, let's work on what is in the parentheses. There are many ways to do it, but let's start with the "easiest" (in some people's opinion).

    What 2 numbers multiplied together equals 3 but added together equals 4? Answer: 3 and 1.

    ^^ The reason for the question above is basically the reverse of FOIL, aka factoring.

    So you final answer is...

    5 (x+1) (x+3)

    If in the future you come across numbers to large to do the "easiest" method OR if there is a # in front of x^2 that is not 1, just us the quadratic formula....It will solve it every time.

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