## samalami 2 years ago Pre Calc help :( PLEAASSSEEEE

1. samalami

2. kittykat96

crap i remember doing this X| this is so going to kill me now because this part i understood let me think

3. samalami

eeek it's an emergency :(

4. kittykat96

do you have notes for this showing how to do it?

5. samalami

i don't need 32

6. kittykat96

ahhhh im going to die trying to remember this is so easy too im thinking too hard

7. nitz

i am not able to open the file

8. samalami

how can I post it so you can see it?

9. nitz

can u post the question directly?

10. samalami

$33. Find the values of x and y for which \left[\begin{matrix} 2y+5 \\ y-2 \end{matrix}\right] =\left[\begin{matrix} x-1 \\ 3x\end{matrix}\right] is true.$

11. samalami

33. Find the values of x and y for which if you couldn't read that sorry

12. Azteck

$6x -4y=12$ $y=\frac{3}{2}x-3$ $m_{N}=-\frac{2}{3}$ $m_{N}=-\frac{2}{k}$ Therefore k=3

13. Azteck

Oops you don't need 32. Nvm.

14. samalami

I apologize :/ can you help with the others??

15. Azteck

$x-2y=6[1]$ $3x-y=-2[2]$ $[1]\times 3$ $3(x-2y)=3(6)$ $3x-6y=18[3]$ $[2]-[3]$ $(3x-y)-(3x-6y)=(-2)-(18)$ $5y=-20$ $y=-4$ Substitute the y-value (ie. -4) into any of the three equations above (ie. [1], [2], [3]) to find the x-value.

16. samalami

THANK YOU SO MUCH!!! 34??

17. Azteck

I don't get the format of 34. That's a question foreign to me. What topic is that question from?

18. Azteck

Is that absolute values?

19. completeidiot

i would assume its find the determinant of course i could be wrong

20. samalami

its to solve the matrix

21. completeidiot

you cant "solve" a matrix http://en.wikipedia.org/wiki/Determinant

22. samalami

I apologize!! it is to find the determinant

23. Azteck

You don't need anyone's help with that. Just read the wiki page. It shows you what to add and subtract.

24. Azteck

$\left[\begin{matrix}a & b & c \\ d & e & f \\ g & h & i \end{matrix}\right]$ $aei+bfg+cdh-ceg-bdi-afh$