Question

Unfortunately, due to a couple of pitiful people (some poor kids who got so lost in life, they resulted to spamming), I’m having to repost this:
OK, so I was learning about how to factorize a quadratic polynomial. And I also wrote notes on it. Now, even though I know that my notes are definitely correct, I’m getting stuck at a certain point. Please look at the attached photo, and explain why the variable X and the number 4 have been removed when we get the factors. I’d greatly appreciate it. Thanks!

Answer 1

Answer:

so when factorising, you first remove the common factors. in this case it is (x+3)

so what is remaining is the x and 4

you group that together.

my teacher explained that when factorising, after removing the common factor then you divide each term by the common factor, and then group the answers to that in brackets.

so it will be,

$x(x + 3) + 4(x + 3) \\ (x + 3)( \frac{x(x + 3)}{x + 3} + \frac{4(x + 3)}{(x + 3)}$

so basically whats left after dividing, is x and 4 because the x+3 cancel off.

and thats how you get the answer of

(x+3)(x+4)

hope this helps;)