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

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.

Lcm of 6 and 8 is 24lcm of 4 and 12 is 12lcm of 11 and 12 is 132 lcm of 3 and 6 is 6