$\left(7,8:\frac{3}{4}\right)-\left(7,8\cdot \frac{3}{4}\right)=\left(\frac{78}{10}:\frac{3}{4}\right)-\left(\frac{78}{10}\cdot \frac{3}{4}\right)=\left(\frac{{\sout{78}}^{26}}{{\sout{10}}^5}\cdot \frac{{\sout{4}}^2}{{\sout{3}}^1}\right)-\frac{234}{40}=$