Question

Să se afle x inclus în Q doar a ,e,f și g​

Answer 1

Răspuns:

a)

$7(x + 1) = 5 \times 4.2 \\ 7x + 7 = 21 \\ 7x = 21 - 7 = 14 \\ x = 14 \div 2 = 7$

e)

Explicație pas cu pas:

$\frac{ \frac{1}{3} + \frac{13}{6} }{x } = \frac{1}{ \frac{2}{5} } \\ \frac{ \frac{2 + 13}{6} }{x} = \frac{1}{ \frac{2}{5} } \\ \frac{ \frac{15}{6} }{x} = \frac{1}{ \frac{2}{5} } \\ x = \frac{15}{6} \times \frac{2}{5} \\ x = \frac{30}{30 } = 1$

f)

$\frac{ \frac{4}{100} }{2x} \frac{ \frac{1}{10} }{ \frac{25}{2} } \\ \frac{4}{100} \times \frac{25}{2} = 2x \times \frac{1}{10 \\ } \\ \frac{100}{200} = \frac{2x}{10} \\ \frac{1}{2} = \frac{x}{5} \\ 2x = 5 \\ x = \frac{5}{2}$

g)

$\frac{ \frac{1}{3} + \frac{1}{3} \times \frac{1}{3} }{ x + \frac{1}{5} } = \frac{4}{9} \\ \frac{ \frac{1}{3} + \frac{1}{9} }{x + \frac{1}{5} } = \frac{4}{9} \\ \frac{ \frac{3 + 1}{9} }{x + \frac{1}{5} } = \frac{4}{9} \\ \frac{ \frac{4}{9} }{x + \frac{1}{5} } = \frac{4}{9} \\ \frac{4}{9} \times 9 = 4(x + \frac{1}{5} ) \\ 4x + \frac{4}{5} = 4 | \times 5 \\ 20x + 4 = 20 \\ 20x = 20 - 4 =1 6 \\ x = \frac{16}{20} = \frac{4}{5}$