The answer to the math question
48 = 2*2*2*2*3
84 = 2*2*3*7
Looking for common factors we get the GCF to be 2*2*3 = 12
Its B
Look over all of the possible answers. If any of them contains either M or N or both, the result is irrational. There's one exception: N^2 produces a rational number because the radical disappears.
Infinitely many solutions, you need to do the distributive property.