Răspuns:
[tex]( - \frac{5}{3} ) \div ( - 15) = ( - \frac{5}{3} ) \times ( - \frac{1}{15} ) = \frac{ (- 5 )\times ( - 1)}{( - 3) \times ( - 15)} = \frac{5}{45 } = \frac{1}{9} [/tex]
[tex]( - 0.(4) \div ( - 2 \frac{1}{3} )) =( ( - \frac{4}{9}) \div ( - \frac{7}{3} )) = ( - \frac{4}{9} ) \times ( - \frac{3}{7}) = \frac{12}{63} = \frac{4}{21} [/tex]
[tex]( - \frac{2}{3} ) \div ( - \frac{4}{9} ) + \frac{3}{7} \div ( - \frac{4}{49} ) = ( - \frac{2}{3} ) \times ( - \frac{9}{4} ) + \frac{3}{7} \times ( - \frac{49}{4} ) = \frac{18}{12} + ( - \frac{147}{28} ) = \frac{7 \times 18}{7 \times 12} + ( - \frac{3 \times 147}{3 \times 28}) = \frac{126}{84} + ( - \frac{441}{84} ) = - \frac{315}{84} [/tex]
[tex]0.12 \div (0.2 - \frac{6}{10} ) \times (0.1 - 1 \frac{2}{5} ) = \frac{12}{100} \div ( \frac{2}{10} - \frac{6}{10} ) \times ( \frac{1}{10} - \frac{7}{5} ) = \frac{12}{100} \div ( - \frac{4}{10} ) \times ( \frac{1}{10} - \frac{2 \times 7}{2 \times 5} ) = \frac{12}{100} \times ( - \frac{10}{4} ) \times ( \frac{1}{10} - \frac{14}{10} ) = ( - \frac{120}{400} )\times ( - \frac{13}{10} ) = ( - \frac{120 \div 10}{400} ) \times ( - \frac{13}{10 \div 10} ) = ( - \frac{12}{400} ) \times ( - \frac{13}{1} ) = ( - \frac{12 \div 4}{400 \div 4} ) \times ( - \frac{13}{1} ) = ( - \frac{3}{100} ) \times ( - \frac{13}{1} ) = \frac{39}{100} = 0.39 [/tex]
Explicație pas cu pas:
[tex] - \times - = + [/tex]
[tex] + \times - = - [/tex]
[tex] + \times + = + [/tex]
[tex] \frac{a}{b} \div \frac{c}{d} = \frac{a}{b} \times \frac{d}{c} [/tex]
împărțirea fractiilor de face astfel : înmulțești prima fractie cu inversul celei de-a doua ( si respecti regula semnelor daca este nevoie)
[tex]a \frac{b}{c } = \frac{a \times c + b}{c} [/tex]
[tex]a.(b) = \frac{ab - a}{cifre \: de \: 9 = numr \: nr \: din \: paranteza} [/tex]
