## evy15 3 years ago use factoring to solve (x-1)^2-9=0

1. Skaematik

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2. viniterranova

First at all you should develop the expression between parentesis.

3. evy15

is this using factoring? I need to use all methods

4. evy15

isn't this extracting the square root

5. evy15

@viniterranova do u mean foil it?

6. viniterranova

If you quadratic trinomial for (x-1)^2 you will find. x^2+2x+1=9, so x^2+2x-8=0

7. evy15

and that's for the factoring method right???

8. viniterranova

Pay attetion. Just plug the x´s values +3 and -3 in the (x-1)^2=9. See if this is values are valid for the expression.

9. viniterranova

x^2+2x-8= 0 ; (x-4)(x+2)=0

10. evy15

well i just wanna be sure

11. viniterranova

Just solve the expression (x-4)(x+2)=0.

12. evy15

wait, im not there yet, so you move the 9 to the other side, and foil (x-1)^2 and I got x^2-2x+1?

13. viniterranova

Just pass the 8 for the first term of the equation and subtract it. and you got x^2+2x-8= 0

14. evy15

is thiscorrect

15. evy15

isn't it a -2x

16. evy15

@Skaematik

17. viniterranova

Yes, it´s -2x. Sorry for my lack of attention. So, the expression is x^2-2x-8=0

18. evy15

and are the answers I got correct?

19. evy15

@Skaematik can u check my work

20. evy15

@viniterranova I saw ur work, I understand now