Question

find (a) the GCF and (b) the LCM of the following monomial

9x^2y and 36xy^3

Answer 1

help plz can u tell me how to find them

Answer 2

the GCF - the highest common factor of 2 or more numbers is the highest number which divides exactly into them
what do u think the GCF of 9 and 36 is?

Answer 3

similarly for variables
what is GCF of x and x^2? - it is x

Answer 4

9 would be the highest common factor right

Answer 5

taks 2 other numbers - 2 and 6 - the GCF is 2 because 2 divides into 2 and 6 and its the greatest number able to do this

Answer 6

yes - 9 is correct

Answer 7

highest - greatest same thing in US they say GCF whereas in UK its HCF

Answer 8

but why is it - ? it would be 9 x no ?

Answer 9

9 is GCF of number bit only
x is GCF of x and x^2
and you now need to find GCF of y and y^3 which is what?

Answer 10

its y

Answer 11

so the final answer would be 9xy because these are the gcf of all three

Answer 12

dead right

so the GCF of the two expressions is

9xy

Answer 13

wow thanks alot! u explained it very well i realli appreciate it :)

Answer 14

yw

Answer 15

:)

Answer 16

LCM = lowest common multiple

eg LCM of 4 and 8 is 8
lcm of 6 and 9 is 18

Answer 17

for 9 and 36 it is 36

Answer 18

a sure way of finding lcm - especially for large numbers is to find the prime factors first

eg 6 and 9:

6 = 2 * 3
9 = 3 * 3

as there is a match of one pair of 3's in the two factors you only use 3 once when working out lcm- you also include all other factors

so we get
2 *3 * 3 = 18

Answer 19

for x and x^2 lcm = x^2
for y and y^3 lcm = what

Answer 20

so 3 *3 = 9
6*6= 36 im confused

Answer 21

there is no need to use the factor method for 9 and 36 because 9 divides into 36 exactly so the lowest common multiple must be 36

but you haven't got the PRIME factors for 36 : - 6 not prime number

9 = 3 * 3
36 = 2 * 2 * 3 * 3

there's 2 pairs of matching 3's so we need 3 * 3

so lcm = 2*2 *3*3 = 36

i hope i haven't complicated things too much

if you have numbers like 2 and 8, or 3 and 9, 12 and 48 where one number divides exactly into the other the lcm is of course the largest of the 2 numbers

Answer 22

i did an LCM of 28 35 and 42 and i got 7

Answer 23

thank u very much for taking the time to make me understand