Відповідь:

7. [tex]\frac{9a-ab}{18a}=\frac{a(9-b)}{18a}=\frac{9=b}{18}[/tex]  Г

8. [tex]=\frac{3p}{3p+2q}-\frac{9p^{2} }{(3p+2q)^{2} }=\frac{3p(3p+2q)-9p^{2} }{(3p+2q)^{2} }=\frac{9p^{2}+6pq-9p^{2}}{(3p+2q)^{2}}=\frac{6pq}{(3p+2q)^{2}}[/tex]

[tex]=\frac{4}{(c-6)(c+6)}-\frac{2}{c(c-6)}=\frac{4c-2(c+6)}{c(c-6)(c+6)}=\frac{4c-2c+12}{ c(c-6)(c+6)}=\frac{2c+12}{c(c-6)(c+6)}=\frac{2(c-6)}{c(c-6)(c+6)}=\frac{2}{c^{2}+6c}[/tex]