## anonymous one year ago anyone good at multiplying polinolyals?

1. jim_thompson5910

2. anonymous

(y+2)(x+3)

3. jim_thompson5910

what I would do is create a table like this |dw:1440551733478:dw|

4. jim_thompson5910

the y+2 goes up top |dw:1440551751828:dw|

5. jim_thompson5910

and the x+3 goes off to the side |dw:1440551769374:dw|

6. jim_thompson5910

to fill this table out, we just multiply the headers example: 2 times 3 = 6 which goes in the second row, second column |dw:1440551792711:dw|

7. jim_thompson5910

do you see how to fill out the rest?

8. anonymous

kinda but the first one no

9. jim_thompson5910

x times y is simply xy |dw:1440551935391:dw|

10. jim_thompson5910

2 times x is equal to what?

11. anonymous

2x

12. jim_thompson5910

yes |dw:1440552012525:dw|

13. jim_thompson5910

and the last box?

14. anonymous

3y

15. jim_thompson5910

|dw:1440552095890:dw|

16. jim_thompson5910

now you just add up everything in the boxes \[\Large xy + 2x + 3y + 6\] there are no like terms to combine so we leave it as that

17. jim_thompson5910

this all means \[\Large (x+3)(y+2) = xy + 2x + 3y + 6\]

18. anonymous

3x 4y and 6

19. jim_thompson5910

what do you mean?

20. anonymous

21. anonymous

but idk what to do with the 6

22. jim_thompson5910

you cannot add 3x to 2y to get 5x or 5y or 5xy they aren't like terms

23. anonymous

24. jim_thompson5910

\(\Large xy + 2x + 3y + 6\) is as simplified as it gets

25. jim_thompson5910

there is no y term other than the 3y the xy cannot be added to 3y to get 4y

26. anonymous

so i dont need to use horizontal or vertical method?

27. jim_thompson5910

you could if you want, but I prefer the table.

28. jim_thompson5910

the horizontal or vertical method makes it hard to keep track of the individual terms whereas the table doesn't have that problem

29. anonymous

so are there going to be other probs where they are more simplified?

30. jim_thompson5910

yes, for example (x+2)(x-7) |dw:1440552711856:dw|

31. jim_thompson5910

|dw:1440552729820:dw|

32. jim_thompson5910

we now have like terms 2x and -7x they combine to -5x

33. jim_thompson5910

so, (x+2)(x-7) = x^2 - 5x - 14

34. anonymous

oh ok

35. anonymous

thanks

36. jim_thompson5910

no problem