## jazzyfa30 2 years ago factoring: x2 - 3x - 28 = 0

1. jazzyfa30

@Kidkush24 help

2. hartnn

can you find 2 numbers whose sum is -3 and product is -28 ?

3. jazzyfa30

7 and 4

4. hartnn

one of them is negative, which ?

5. jazzyfa30

-7 and 4

6. hartnn

correct! so, split up -3x as -7x+4x x^2 -7x+4x-28 now factor out x from first 2 terms and 4 from last two, can you ?

7. jazzyfa30

ummmm idthink so

8. hartnn

ok, to factor out x from x^2-7x, we get x (x-7) and 4 from 4x-28. we get +4(x-7) so, x(x-7)+4(x-7) factor out (x-7) from this!

9. jazzyfa30

-7 4(x-7)??????

10. hartnn

if you take (x-7) out from those 2 terms, what remains is (x-7) (x+4) thats it! factored.....

11. hartnn

and don't forget the = 0 (x-7)(x+4) = 0 do you need to solve it too ? or just factoring ?

12. jazzyfa30

just factor can u help me with a few more

13. hartnn

did you get this one properly ?

14. jazzyfa30

yes

15. hartnn

yeah, then i can help u with next problems...just post them in a new post...so that if i am busy, others can help you too!