## alli4476 2 years ago Hey you guys I REALLY NEED HELP

1. alli4476

what is the lcm of -14a^3b^7 and 21a^5b^2

2. alli4476

isit 7a^8b^9

3. jim_thompson5910

what's the LCM of 14 and 21

4. alli4476

42

5. JuanitaM

for the coefficent - LCM multiply the coefficient - what is the smallest number that both 14 and 21 divide evenly. So look at x^3 and x^5; Do you see that x^5 is the smallest monomial that both x^3 and x^5 divide evenly? ----- And looking at b^7 and b^2; Do you see that b^7 is the smallest?

6. jim_thompson5910

now find the LCM of a^3 and a^5

7. alli4476

wait do I divide 3 and 5

8. jim_thompson5910

you just take the larger exponent so the LCM is a^5

9. jim_thompson5910

the LCM of b^2 and b^7 is b^7

10. jim_thompson5910

all together: LCM of -14a^3b^7 and 21a^5b^2 is 42a^5b^7

11. alli4476

are you sure there is not that answer

12. jim_thompson5910

what answer choices do you have

13. alli4476

here is what I have 7a^8b^9 249a^8b^9 249a^3b^2 7a^3b^2

14. jim_thompson5910

looks like you want the GCF (and not the LCM) then

15. jim_thompson5910

I see the GCF in there, but not the LCM

16. JuanitaM

agreed with Jim :)

17. alli4476

oh yeah sorry guys

18. JuanitaM

your answer for the 7 is correct, but for GCF and exponents; you take the smaller of the exponents

19. alli4476

ok

20. alli4476

so it would be 7a^3b^2

21. alli4476

right

22. jim_thompson5910

you are correct