Expert: Richard J. Raridon - 2/6/2008

Question
In some of the problems I am to reduce, find the illegal values with algebraic fractions,and I am lost :P

10. dividing m^2n^3 by mp
            -----     ---
              p^3     n^2

11. dividing r + 5 by r^2 + 4r - 21
     -------------   -----
     r^2 +  5r - 14   r-2

Finding the lowest common denominator
13. 3 and 7
  ---   ---
 x^3 y  xy^4

14. p + 3 and p + 5
----------    --------
p^2 + 7p + 10  p^2 + 5p + 6

Can you please help me with these. I have tried to work them out, and still can't come to the correct answer.

Answer
10. [m^2n^3/p^3]/[mp/n^2] = [m^2n^3/p^3][n^2/mp] = mn^5/p^4
11. [(r+5)/(r^2+5r-14)]/[(r^2+4r-21)/(r-2)] =
[(r+5)/{(r+7)(r-2)}][(r-2)/{(r+7)(r-3)}] = (r+5)/[(r+7)^2(r-3)]
13. are you adding these?
3/(x^3y)  and 7/(xy^4), LCD = x^3y^4
14. I presume you're multiplying these?
[(p+3)/{(p+2)(p+5)}][(p+5)/{(p+2)(p+3)}] = 1/(p+2)^2