## anonymous one year ago Please help, -3xyz for x = -3/4 , y = 5/9 and z = -8/15

1. anonymous

Its evaluate

2. anonymous

Replace the variable with the numbers they're equal to $-3\left(- \frac{ 3 }{ 4 } \right)\left( \frac{ 5 }{ 9 } \right)\left(- \frac{ 8 }{ 15 } \right)$ You can write 3 as 3/1 if it makes it easier $\left(- \frac{ 3 }{ 1 } \right)\left(- \frac{ 3 }{ 4 } \right)\left( \frac{ 5 }{ 9 } \right)\left(- \frac{ 8 }{ 15 } \right)$ From here, you can cancel common factors and then multiply. Or multiply and then reduce at the end

3. anonymous

I did that, but my teacher was like no.

4. anonymous

- 9 / 4?

5. anonymous

|dw:1441192359993:dw|

6. anonymous

lol what the heck! ? ahh

7. anonymous

im confused now

8. anonymous

|dw:1441192517680:dw|

9. anonymous

|dw:1441192594395:dw|

10. anonymous

|dw:1441192656064:dw|

11. anonymous

There are 3 negative signs, so the answer is negative. So you're left with -2/3

12. anonymous

oh okay, i think i understand!

13. anonymous

if i were to show my work how could i do it an easy way to read?

14. anonymous

It's definitely better to cancel when you can because then you're not left with big numbers, and you might not even have to multiply anything. To show your work, maybe write the problem once, then write it again showing the canceling. Your teacher should understand that as written, it's pretty common

15. anonymous

put it like this

16. anonymous

|dw:1441192972789:dw|

17. anonymous

That second line probably isn't necessary. It just helps with readability.

18. anonymous

lol okay, thanks!

19. anonymous

i have a quiz tommorow so thats why i have to show my work.

20. anonymous

ah ok. You're welcome :)