## anonymous one year ago matrix 2

• This Question is Open
1. anonymous

2. anonymous

ihatethisevenmoremore

3. anonymous

it is not C

4. anonymous

5. anonymous

this is where you say "yeah i am ready even though i hate this even more"

6. anonymous

yeah i am ready even though i hate this even more

7. anonymous

ok the last line has 1, -2 which means $$z=-2$$

8. anonymous

the second to last line has 1, 1, 3 which means $y+z=3$ we know $$z=-2$$ so $y-2=3$or $y=5$

9. anonymous

the first line has 1, a, 2, 2 which means $x+ay+2z=2$ we know $$y=5$$ and $$z=-2$$ so we have $x+4a+2\times (-2)=2$ or $x+5a-4=2$

10. anonymous

solve for $$a$$ and get your answer you can do it or you want help?

11. anonymous

oops i meant "solve for $$x$$"

12. anonymous

its B? then

13. anonymous

yeah B

14. anonymous

okay 1 or 2 more then i promise ill let you go :'(

15. anonymous

i have to say for someone starting out with matrices this is a dumb question but whatever

16. anonymous

yeah i always stay up until 3 to help...

17. anonymous

18. anonymous

I think its D?

19. anonymous

@freckles this one is on you, i always screw this up

20. anonymous

C is out

21. anonymous

i mean matrix C is out

22. anonymous

oh maybe not let me shut up

23. freckles

if we do a m by n times a n by k the we are cool because this will result in a m by k matrix you just have to make sure the inner numbers match if you know what I mean

24. freckles

|dw:1433573306445:dw|

25. anonymous

so BA is ok right?

26. freckles

|dw:1433573324663:dw|

27. anonymous

and CB?

28. anonymous

okay so can CB not work or

29. anonymous

CB ok [2,4][4,1] right?

30. anonymous

oh wait so it's E then??

31. freckles

AB will not work since we have a 1 by 3 times a 4 by 1 3 is not 4 BA will work since we have a 4 by 1 times 1 by 3 1 is 1 CB will work 2 by 4 times 4 by 1 because 4 is 4

32. anonymous

ok ok so LAST ONE

33. anonymous

cheat

34. anonymous

otherwise this is total donkey work that takes like forever with very little bang for your buck it is for a machine, let the machine do it http://www.wolframalpha.com/input/?i=x-2y-z%3D2%2Cy%2B3z%3D1%2C2x-4y-3z%3D3

35. anonymous

you got this?