Question

З поясненням будь ласочка

Answer 1

$\displaystyle\bf\\1)\\\\2^{-2} +2^{-1}=\frac{1}{2^{2} } +\frac{1}{2^{1} } =\frac{1}{4}+\frac{1}{2}=\frac{1}{4} +\frac{2}{4} =\frac{3}{4} =0,75 \\\\2)\\\\3^{-2} -6^{-1}=\frac{1}{3^{2} } -\frac{1}{6^{1} } =\frac{1}{9}-\frac{1}{6}=\frac{2}{18} -\frac{3}{18} =-\frac{1}{18} \\\\3)\\\\0,03^\circ +7^\circ=1+1=2\\\\4)\\\\\Big(9\cdot 3^{-3} -12^{-1} \Big)^{-1}=\Big(9\cdot \frac{1}{3^{3} } -\frac{1}{12} \Big)^{-1} =\Big(9\cdot\frac{1}{27} -\frac{1}{12} \Big)^{-1} =$

$\displaystyle\bf\\=\Big(\frac{1}{3} -\frac{1}{12} \Big)^{-1} =\Big(\frac{4}{12} -\frac{1}{12} \Big)^{-1} =\Big(\frac{3}{12} \Big)^{-1} =\frac{12}{3}=4$