\(a,\dfrac{15}{16}:\left(\dfrac{1}{2}-\dfrac{2}{3}\right)^2\)
\(=\dfrac{15}{16}:\left(-\dfrac{1}{6}\right)^2\)
\(=\dfrac{15}{16}:\dfrac{1}{36}\)
\(=\dfrac{15}{16}\cdot36=\dfrac{135}{4}\)
\(---\)
\(b,\dfrac{15}{34}+\dfrac{7}{21}+\dfrac{19}{34}-\dfrac{15}{17}+\dfrac{2}{3}\)
\(=\left(\dfrac{15}{34}+\dfrac{19}{34}\right)+\left(\dfrac{7}{21}+\dfrac{2}{3}\right)-\dfrac{15}{17}\)
\(=1+\left(\dfrac{1}{3}+\dfrac{2}{3}\right)-\dfrac{15}{17}\)
\(=1+1-\dfrac{15}{17}\)
\(=2-\dfrac{15}{17}\)
\(=\dfrac{34}{17}-\dfrac{15}{17}=\dfrac{19}{17}\)
\(---\)
\(c,1\dfrac{4}{23}+\dfrac{5}{21}-\dfrac{4}{23}+0,5+\dfrac{16}{21}\)
\(=\left(1\dfrac{4}{23}-\dfrac{4}{23}\right)+\left(\dfrac{5}{21}+\dfrac{16}{21}\right)+0,5\)
\(=1+1+0,5\)
\(=2+0,5=2,5\)
\(---\)
\(d,\dfrac{3}{4}\cdot26\dfrac{2}{9}-38\dfrac{2}{9}\cdot\dfrac{3}{4}\)
\(=\dfrac{3}{4}\cdot\left(26\dfrac{2}{9}-38\dfrac{2}{9}\right)\)
\(=\dfrac{3}{4}\cdot\left[26+\dfrac{2}{9}-\left(38+\dfrac{2}{9}\right)\right]\)
\(=\dfrac{3}{4}\cdot\left(26+\dfrac{2}{9}-38-\dfrac{2}{9}\right)\)
\(=\dfrac{3}{4}\cdot\left(-12\right)=-9\)
\(---\)
\(f,-3,75\cdot\left(-7,2\right)+2,8\cdot3,75\)
\(=3,75\cdot7,2+2,8\cdot3,75\)
\(=3,75\cdot\left(7,2+2,8\right)\)
\(=3,75\cdot10=37,5\)
\(---\)
\(g,\left(2\dfrac{1}{2}+0,25\right)-\left(\dfrac{1}{4}-4,25+\dfrac{1}{2}\right)\)
\(=\left(2+\dfrac{1}{2}+\dfrac{1}{4}\right)-\left(\dfrac{1}{4}-\dfrac{17}{4}+\dfrac{1}{2}\right)\)
\(=2+\dfrac{1}{2}+\dfrac{1}{4}-\dfrac{1}{4}+\dfrac{17}{4}-\dfrac{1}{2}\)
\(=\left(2+\dfrac{17}{4}\right)+\left(\dfrac{1}{2}-\dfrac{1}{2}\right)+\left(\dfrac{1}{4}-\dfrac{1}{4}\right)\)
\(=\dfrac{8}{4}+\dfrac{17}{4}=\dfrac{25}{4}\)
#\(Toru\)
