Remember
(abc)/(def)=(a/d)/(b/e)(c/f)
and
(x^m)/(x^n)=x^(m-n)
and
x^-m=1/(x^m)
group like terms
(28/12)(p^9/p^-6)(q^-5/q^7)=
(7/3)(p^15)(q^-12)=
(abc)/(def)=(a/d)/(b/e)(c/f)
and
(x^m)/(x^n)=x^(m-n)
and
x^-m=1/(x^m)
group like terms
(28/12)(p^9/p^-6)(q^-5/q^7)=
(7/3)(p^15)(q^-12)=