1. a)
[tex] \frac{2}{5} + \frac{3}{4} = \frac{23}{20} [/tex]
Amplificam fractiile ca să avem același numitor
b)
[tex] \frac{3}{7} \times ( \frac{2}{5} + \frac{3}{4} = \frac{3}{7} \times \frac{23}{20} = \frac{69}{140} [/tex]
c)
[tex] \frac{3}{7} \times \frac{2}{5} = \frac{6}{35} [/tex]
d)
[tex] \frac{3}{7} \times \frac{2}{5} + \frac{3}{7} \times \frac{3}{4} = \frac{6}{35} + \frac{9}{28} = \frac{24 + 45}{140} = \frac{69}{140} [/tex]
2.
[tex] \frac{5}{4} \times ( \frac{1}{3} - \frac{1}{2} ) = \frac{5}{4} \times \frac{1}{3} - \frac{5}{4} \times \frac{1}{2} [/tex]
Desfacand paranteza de acel rezultat sau putem calcula ambele variante
[tex] \frac{5}{4} \times ( \frac{1}{3} - \frac{1}{2} ) = \frac{5}{4} \times - \frac{1}{6} = - \frac{5}{24} [/tex]
[tex] \frac{5}{4} \times \frac{1}{3} - \frac{5}{4} \times \frac{1}{2} = \frac{5}{12} - \frac{5}{8} = \frac{10 - 15}{24} = - \frac{5}{24} [/tex]
Sper ca te-am ajutat
