Simple Year 9 Maths Help

Hey, I missed a whole week at school, and my Maths teacher is Spanish, and speaks too fast.
It’s only Year 9 stuff, so anyone should be able to help.
I think I’ve done the first lot right, but here’s the second:
The example is:
Factorise 2x� – 8x – 10
2x� -8x – 10 = 2( x� – 4x – 5 )
= 2( x – 5 )( x + 1 )
Here’s number 10.
3x� – 12x + 9
I think I can do it through pattern, but I want to know what happens, and why.
kthxbai
Answer #1
3( x� – 4x + 3 )
=3x� – 12x + 9
Answer #2
3x� – 12x + 9
= 3(x� – 4x + 3 )
= 3(x – 1) (x – 3)
Answer #3
Thanks, but as I said:
I want to know what happens, and why.
Answer #4
oh ok. Well, first, look at the factor of every term, so 3 is a factor of all of those, so you can take that outisde the bracket. then inside the bracket, look at the last term, which is in this case 3. There arent many ways to make a three, so you either have a choce of +1 times +3 or -1 times -3. You would then try both to see if you get the middle term. To get the middle term, you would add those 2 numbers, so -1+(-3) is -4. So last term, you multiply, second term you add. Hope that helps
Answer #5
Thank you! If there’s anything I can do in return, PM me.
Answer #6
other solution
3x� – 12x + 9
= 3(x� – 4x + 3 )
for this u apply this formula
(x� – 4x + 3 ) where x�=a -4x=b 3=c

now formula is this: a(x – x1) (x – x2)= 3(x-1)(x-3)
hope this helps
Answer #7
Uhm, no. Just… no. But thanks anyway. :p