Question

(x^2/18y)-(7y/3z)+(5z^3/12x) how would you find LCD and solve

Answer 1

you can find the LCD by simply multiplyin the denominators: (18y)(3z)(13x)

Answer 2

then adjust each fraction accordingly

Answer 3

the denominators are 18y, 3z and 12x
lcd of the numbers is 18
lcd is 18xyz

Answer 4

so how would I adjust the numerators

Answer 5

multiply the 7y over 3z by six ?

Answer 6

six xy

Answer 7

ok first fractiom :- 18xy / 18y =x so we multiply the numerator by x so this becomes x^3

Answer 8

sorry 18xyz / 18y = xz :- numerator becomes x^2 * xz = x^3z

Answer 9

ok

Answer 10

no it becomes x^3 z / 18xyz - its x^2 * xz to get the numerator

Answer 11

for the second fraction do you multiply it by 6xy?

Answer 12

in a similar way
second fraction becomes (18xyz / 3z ) * 7y = 6xy * 7y = 42xy^2
so fraction becomes 42xy^2 / 18xyz

Answer 13

yes multiply by 6xy

Answer 14

you are getting it!

Answer 15

what about the last one

Answer 16

what would you multiply the numerator by?

Answer 17

i must apoligise dumpling i made a mistake with the LCD - 12 wont go into 18 - the LCD should be 36xyz
this makes the first fraction 2x^3z / 36xyz and the second = 84xy^2 / 36xyz

Answer 18

oh ok so multiply the third by three, but after you combine all three would you need to simplify it

Answer 19

third numerator is (36xyz / 12x) * 5z^3 = 3yz*5z^3 = 15yz^4
so fraction is 15yz^4 / 36xyz

Answer 20

yes we now have to combine all 3 and simplify - its quite tedious algebra i'm afraid

Answer 21

no need to simplify right, just put all under same denominator

Answer 22

could you simplify the 84and 36

Answer 23

no as you said you put it all under the same denominator - it cant be simplified any further

so its [2x^3z + 84 xy^2 + 15yz^4)] / 36xyz

Answer 24

- this was pretty messy but we got there in the end
you cannot simplify terms when you have a sum like this as the numerator You cannot factori the numerator so cancellation is not possible.

Answer 25

thanks you helped a lot