strange notation, but correct.
text formatting doesn't work too well here, especially if you omit the horizontal lines. Better just to write
3m/(m+n) and 3n/(m-n)
or even
(3m)/(m+n) and (3n)/(m-n)
in case you make the numerators more complicated later...
What is the LCD of these
3m 3n
m+n m-n
(m+n)(m-n)**
2m
2mn
(m-n)^2
2 answers
What I have so far
1. B
2. C
3. B
4. A
5. D
6. A
7. B
1. B
2. C
3. B
4. A
5. D
6. A
7. B