## anonymous one year ago I just need someone to check my answers in using matrices to determine the coordinates of matrices.

1. anonymous
2. anonymous

For both answers I got C. http://prntscr.com/8g2v9u

3. LynFran

for this 1...its A http://prntscr.com/8g2v9u

4. anonymous

Ah, that was my first assumption, but I second guessed myself.

5. LynFran

and for the other its A too

6. LynFran

we use the x axis matrix $\left[\begin{matrix}1 & 0 \\ 0 & -1\end{matrix}\right]$times it by each vertex to find solution of its it image

7. LynFran

the 270 degree matrix $\left[\begin{matrix}0 & 1 \\ -1 & 0\end{matrix}\right]$we do the same here too

8. anonymous

Thanks! I really appreciate your explanations because matrices have been giving me such a hard time.

9. LynFran

example with vertices V(8,4) and we want its image that was revolve 270 degree we multiply that by its matrix $\left[\begin{matrix}0 & 1 \\ -1 & 0\end{matrix}\right]*\left(\begin{matrix}8 \\ 4\end{matrix}\right)$$\left(\begin{matrix}0*8+(-1)*4 \\ (-1)*8+0*4\end{matrix}\right)$we get $\left(\begin{matrix}-4 \\ -8\end{matrix}\right)$as the image of V

10. anonymous

Ah, I see. Do you think you can help with scale factor with matrices as well?

11. LynFran

ok

12. anonymous

So this is my question. http://prntscr.com/8g302o I got A, but I was just guessing since the others didn't look right, but the points aren't exact, so it's kind of confusing.

13. anonymous

Actually I think it's this one! http://prntscr.com/8g30iv

14. LynFran

|dw:1442193863405:dw|

15. LynFran

ok so w(-1, 2).. z(-2, -4)...x(5,5)...y(5,3)

16. LynFran

its images is being multiple by 3

17. LynFran

so for image w we get 3(-1, 2) which give (-3, 6)

18. anonymous

Ahh, so that's how you multiply it, thanks a lot.

19. LynFran

yep|dw:1442194345221:dw|are the coordinates of image

20. anonymous

Okay, I understand now.