Question

Which fraction represent the given fraction rewritten with their LCD?

1/3x-9y, 6/5x-15y



a. 2/8x-21y , 12/8x-21y


b. 5(x-3y)/15(x-3y) , 15(x-3y)^2


c. 5/15(x-3y) , 18/15(x-3y)


d. 5/15x-135y , 18/15x-135y

Answer 1

Please, use ( ) around fractional coefficients:

1/3x-9y, 6/5x-15y should (probably) be written as (1/3) - 9y and (6/5)x - 15 y.

The LCD here is 3(5) = 15.


Mult. 1/3x-9y and 6/5x-15y by 15, and then divide the result by 15:

15 [ (1/3)x - 9y and (6/5)x - 15 y ]
---------------------------------------------
15


This simplifies to:

5x - 135y and 18x - 225y
------------ --------------
15 15

These fractions are equivalent to the original ones, but now the common denominator, 15, is evident.