how do you add or subtract a rational expression show steps
12 2
--- _ ---
5y2 5yz

Question

how do you add or subtract a rational expression show steps
12         2
---  _  ---
5y2      5yz

debbieg · Answer

What is your LCD?

anonymous · Answer

im guessing 5 but i could be wrong

luigi0210 · Answer

You have part of your denominator, but not all of it 
btw Welcome to Openstudy :)

debbieg · Answer

Your denominators (if I'm interpreting what you wrote correctly) are$$\large 5y^2$$and $$\large 5yz$$
The LCD has to be a MULTIPLE of BOTH denominators. So it has to have a factor of every factor that's in each denominator.

$$\large 5y^2$$ has a factor of 5, and 2 factors of y. So the LCD must have a factor of 5 and 2 factors of y.

$$\large 5yz$$ has a factor of 5, a factor of y, and a factor of z. Now, we already said that the LCD will have a factor of 5, so that's covered. We said that it will have 2 factors of y, so that will cover the ONE factor of y that's needed here. What we DON'T have yet in our LCD is the one factor of z that we need because of this 2nd den'r, so we have to throw that in. 

So we need: one factor of 5 (required by both den'rs); two factors of y (required by the first den'r, and will cover the one factor needed by the 2nd den'r); and one factor of z.

So line those up in a product, and that will be your LCD.