7: \(\left(2^2:\frac43-\frac12\right)\cdot\frac65-\left(-\frac{7}{15}\right)^0\)
\(=\left(4\cdot\frac34-\frac12\right)\cdot\frac65-1\)
\(=\left(3-\frac12\right)\cdot\frac65-1=\frac52\cdot\frac65-1=3-1=2\)
8: \(\left(1+\frac23-\frac14\right)\left(0,8-\frac34\right)^2\)
\(=\left(\frac{12}{12}+\frac{8}{12}-\frac{3}{12}\right)\cdot\left(\frac45-\frac34\right)^2\)
\(=\frac{17}{12}\cdot\left(\frac{1}{20}\right)^2=\frac{17}{12}\cdot\frac{1}{400}=\frac{17}{4800}\)
9: \(\left(-\frac25\right)^2\cdot\left|\frac13-\frac35\right|-\frac25\cdot\sqrt{\frac{1}{25}}+1\frac13\)
\(=\frac{4}{25}\cdot\left|\frac{5}{15}-\frac{9}{15}\right|-\frac25\cdot\frac15+\frac43\)
\(=\frac{4}{25}\cdot\frac{4}{15}-\frac{2}{25}+\frac43=\frac{16}{375}-\frac{30}{375}+\frac{500}{375}=\frac{486}{375}=\frac{162}{125}\)
10: \(\left(\frac13\right)^{50}\cdot\left(-9\right)^{25}-\frac23:4\)
\(=\frac{1}{3^{50}}\cdot\left(-1\right)\cdot3^{50}-\frac{2}{3\cdot4}\)
\(=-1-\frac16=-\frac76\)
11: \(\frac{\left.\left(3\cdot8\right)^3\cdot5\right.}{2^9\cdot15^2}=\frac{3^3\cdot5\cdot8^3}{2^9\cdot3^2\cdot5^2}=\frac{2^9\cdot3^3\cdot5}{2^9\cdot3^2\cdot5^2}=\frac35\)
12: \(\frac{2\cdot6^9-2^5\cdot18^4}{2^2\cdot6^8}=\frac{2\cdot2^9\cdot3^9-2^5\cdot2^4\cdot3^8}{2^2\cdot2^8\cdot3^8}\)
\(=\frac{2^9\cdot3^8\left(3-1\right)}{2^{10}\cdot3^8}=\frac{2^9\cdot2}{2^{10}}=1\)
