R = Ronald's age now.
C = Carlo's age now.
R-9 = Ronald's age 9 years ago
C-9 = Carlo's age 9 years ago.

C = R + 6

Substitute R + 6 for C in:

            C > 46
        R + 6 > 46
            R > 40

So thare are many possibilities:
Ronald is 41 and Carlos is 47
Ronald is 42 and Carlos is 48
Ronald is 43 and Carlos is 49
Ronald is 44 and Carlos is 50
Ronald is 45 and Carlos is 51

until the ages get so large that 
nobody lives to be that old.
 
So there is not just one answer. Did you leave 
something out?

----------------------------

The first two terms have a common monomial factor of 3.  Since both those terms
are positive, we just group them with a set of parentheses:



The next two terms have a common monomial factor of 4x.  Since both those terms
are positive, we just group them with a set of parentheses as before:



The next two terms have a common monomial factor of 5c.  Since both those terms
are positive, we just group them with a set of parentheses as before:



The next two terms have a common monomial factor of 5r.  Since both those terms
are positive, we just group them with a set of parentheses as before:



Now we have to watch it because the first of the last two terms is a
negative. In that case we insert not just a parentheses but also a
plus sign + and a parentheses before the negative term.



That last pair of factors has common monomial factor . If
the first term is negative we always take out a negative.

----------------------------

We determined them above when we did the grouping. Now we'll factor them 
all out, so we have:



Notice that when you factor out a negative as in the last
parentheses, you change both sign inside the parentheses.

Edwin