What does the R stand for when attached to a molecule?

R is an abbreviation for radical, when the term radical applied to a portion of a complete molecule (not necessarily a free radical), such as a methyl group.

telophase and anaphase

try using substitution:

x + y - 6 = x - y. (i'm not giving you the exact answer). since 0 = x - y, then sub 0 in the equation with x - y. combine your like terms, and then use inverse operations, and you'll have your answer.

: -)