## iwanttogotostanford one year ago PRACTICE ACT Q: What expression must the center cell of the table below contain so that the sum of each row, each column, and each diagonal are equivalent?(DIAGRAM DRAWN BELOW)

1. iwanttogotostanford

|dw:1444183648198:dw|

2. iwanttogotostanford

@zepdrix @Nnesha @Musicdude

3. zepdrix

How much does each column or row add up to? Have you tried calculating one of them yet? :)

4. zepdrix

Like just try the top row maybe, $$\large\rm x+8x-3x$$

5. iwanttogotostanford

no haha

6. iwanttogotostanford

I will try

7. iwanttogotostanford

yes i tried that now

8. zepdrix

and...?

9. iwanttogotostanford

well I see a pattern

10. iwanttogotostanford

it is 2x?

11. zepdrix

Yes, the missing amount is a 2x. I'm not what pattern you're talking about though.. hmm

12. anonymous

everything adds up to 6x....with the 2x in the middle

13. iwanttogotostanford

but when I add up the first row accrues, I get 5x^2

14. zepdrix

That's what I was hoping you would figure out on your own, that the add up to 6x, but oh well...

15. anonymous

oops....sorry

16. iwanttogotostanford

but I added up the first across and it doesn't equal 6x...?

17. zepdrix

$\large\rm apple+apple\ne apple^2$Not sure where the square came from, hmm :d

18. zepdrix

$\large\rm apple+apple = two~apples$

19. iwanttogotostanford

but don't two x equal x^2???

20. anonymous

not when adding, just when multiplying

21. zepdrix

$$\large\rm x+x\ne x^2$$ no :(

22. iwanttogotostanford

oh oak forgot that rule

23. anonymous

x + x = 2x x * x = x^2

24. zepdrix

you have an apple, 8 more apples, then take away 3 apples.

25. iwanttogotostanford

but if everything is supposed to equal to 6x then why doesn't the first row equal that??? They are all supposed to be equal

26. zepdrix

how many apples?

27. anonymous

they do equal 6x

28. iwanttogotostanford

x+8x-3x doesn't equal 6?

29. zepdrix

bruh...

30. zepdrix

lol

31. anonymous

1 + 8 - 3 = ?

32. iwanttogotostanford

ok OK haha i got it

33. iwanttogotostanford

i forgot that X counted as a 1

34. iwanttogotostanford

.....

35. zepdrix

oh :o