I need help with factorizing quadratic trinomials. I have a math test tomorrow, and the math book's explanation doesn't make any sense at all. Could someone explain to me how to go about factorizing quadratic trinomials?

Some problems:

x^2+9x+20

x^2-2x-8

3x^2-6x-24

-4+4x-x^2

Question

I need help with factorizing quadratic trinomials. I have a math test tomorrow, and the math book's explanation doesn't make any sense at all. Could someone explain to me how to go about factorizing quadratic trinomials?

Some problems:

x^2+9x+20

x^2-2x-8

3x^2-6x-24

-4+4x-x^2

anonymous · Answer

you need to tackle them one by one the easy one first

parthkohli · Answer

First two and last two terms. Just for a little sample, I'd do the first.
You have $\rm 2a + 2 +a b + b$
First two - $\rm 2(a + 1)$
Last two - $\rm b(a + 1)$

You're left with $\rm 2(a + 1) + b(a + 1) = (2 + b)(a + 1)$

anonymous · Answer

@ParthKohli Right, thanks. What about, say, $$x^2+9x+20$$?

anonymous · Answer

4x5=20  use that

anonymous · Answer

also 4+5 =9

anonymous · Answer

x^2+9x+20=0
(x+4)(x+5)=0  check them by mult n add
x^2 +4x+5x+20=0
x^2+9+20=0 checked

anonymous · Answer

x^2-2x-8=0 hint -4(2)=-8 and -4+2=-2

anonymous · Answer

can you try that?

anonymous · Answer

Alright, got it. Thanks! :)

anonymous · Answer

ok YW good luck :D