## anonymous 4 years ago would the answer of (a − b)(a − b) be a^2 - ab^2 - b^2

1. anonymous

FOIL First: a*a = a^2 Outside = -ab Inside = -ab Last = -b(-b) = +b^2 What do we do with the -ab and the -ab?

2. anonymous

Tkink -x + -x = -2x

3. anonymous

I know to combine itt

4. anonymous

@chungerforever remember when we had $$5x+5x=10x$$? don't change the exponents here either

5. anonymous

$$-ab-ab=?$$

6. anonymous

oh minus! so just ab?

7. anonymous

$$-10-10=?$$

8. anonymous

oh I understand, so the answer is just a^2 - b^2?

9. anonymous

hold the phone, careful arithmetic $$-10-10=?$$

10. anonymous

hint, it is not 0

11. anonymous

I'm sorry I have no idea, I'm not good at algebra ):

12. anonymous

-10?

13. anonymous

don't fret, we will work it out, but i was asking an arithmetic question $$-10-10=-20$$

14. anonymous

$$-100-100=?$$

15. anonymous

-200?

16. anonymous

yes that is it !

17. anonymous

$$-7-7=?$$

18. anonymous

-14

19. anonymous

ok good now we can move on to variables

20. anonymous

$-10-10=-20$ $-100-100=-200$ $-7-7=-14$ $-12-12=-24$ and so on how about $-x-x$? well this must be the same as the others, namely $-x-x=-2x$

21. anonymous

so -2ab?

22. anonymous

notice that the exponent does not change spend $20, spend another$20 you have spent $$2\times 20=40$$ yes you have it !

23. anonymous

so "final answer" for $$(a-b)(a-b)$$ is ??

24. anonymous

a^2 - 2ab - b^2?

25. anonymous

yes that is it!

26. anonymous

thank you so much! and sorry I was taking a while to reply. But thanks again I appreciate it (:

27. anonymous

yw good work, hope you are understanding a bit more about combining like terms