Задание 42

а) $16\times {\left(\begin{array}{c}\hfill \frac{1}{4}\end{array}\right)}^2-8\times {\left(\begin{array}{c}\hfill \frac{1}{2}\end{array}\right)}^4=16\times \left(\begin{array}{c}\hfill \frac{1}{16}\end{array}\right)-8\times \left(\begin{array}{c}\hfill \frac{1}{4}\end{array}\right)$ = $1-\frac{1}{2}$ = $\frac{1}{2}$;

б)$3\times {\left(\begin{array}{c}\hfill \frac{1}{5}\end{array}\right)}^2+16\times {\left(\begin{array}{c}\hfill \frac{1}{4}\end{array}\right)}^2=3\times \frac{1}{25}+16\times \frac{1}{16}$ = $\frac{3}{25}+1$ = $1,12$;

в)$18\times {\left(\begin{array}{c}\hfill \frac{1}{3}\end{array}\right)}^2-15\times {\left(\begin{array}{c}\hfill \frac{2}{5}\end{array}\right)}^2=18\times \frac{1}{9}-15\times \frac{4}{25}$ = $2-2,4$ = $-0.4$.