Question

aceste exerciții!!! urgent! (toate) ​

Answer 1

Răspuns:

1.

$\frac{24}{x} = \frac{6}{5} \\ \\ x = \frac{24 \times 5}{6} = 20$

2.

$\frac{x}{25} = \frac{7}{10} \\ \\ x = \frac{25 \times 7}{10} = \frac{35}{2} = 17 \frac{1}{2}$

3.

$\frac{15}{ \frac{5}{7} } = \frac{6}{ \frac{5}{x} } \\ \\ 21 = \frac{6x}{5} \\ \\ x = \frac{35}{2}$

4.

$\frac{x}{ \frac{1}{2} } = \frac{16}{ \frac{3}{2} } \\ \\ 2x = \frac{32}{3} \\ \\ x = \frac{16}{3}$

5.

$\frac{7 \times {2}^{6} \div 28 - {7}^{0} }{x} = \frac{5}{2} \\ \\ \frac{ \frac{ {2}^{6} }{ {2}^{2} } - 1 }{x} = \frac{5}{2} \\ \\ \frac{16 - 1}{x} = \frac{5}{2} \\ \\ \frac{15}{x} = \frac{5}{2} \\ \\ x = \frac{15 \times 2}{5} = 6$

6.

$\frac{14}{x} = \frac{2.1}{0.54} \\ \\ x = \frac{18}{5}$

7.

$\frac{25}{6x} = \frac{5}{9} \\ \\ 6x = \frac{25 \times 9}{5} = 45 \\ \\ x = \frac{45}{6} = \frac{15}{2} = 7 \frac{1}{2}$

Answer 2

Răspuns:

$f) \frac{24}{x} = \frac{6}{5} \\ 6x = 24 \times 5 \\ 6x = 120 \\ x = 120 \div 6 \\ x = 20$

$2)d) \frac{x}{25} = \frac{7}{10} \\ 10x = 25 \times 7 \\ 10x = 175 \\ x = 17.5$

$3)c) \frac{15}{ \frac{5}{7} } = \frac{6}{ \frac{5}{x} } \\ 15 \times \frac{5}{x} = 6 \times \frac{5}{7} \\ \frac{75}{x} = \frac{30}{7} \\ 75 \times7 = 30x \\ 30x = 525 \\ x = \frac{525}{30} = \frac{105}{6} = \frac{35}{2}$

$d) \frac{x}{ \frac{1}{2} } = \frac{16}{ \frac{3}{2} } \\ x \times \frac{3}{2} = 16 \times \frac{1}{2} \\ \frac{3x}{2} = \frac{16}{2} \\ 3x \times 2 = 16 \times 2 \\ 6x = 32 \\ x = \frac{32}{6} = \frac{16}{3}$

$4)b) \frac{7 \times {2}^{6} \div 28 - {7}^{0} }{x} = \frac{5}{2} \\ \frac{7 \times 64 \div 28 - 1}{x} = \frac{5}{2} \\ \frac{448 \div 28 - 1}{x} = \frac{5}{2} \\ \frac{16 - 1}{x} = \frac{5}{2} \\ \frac{15}{x} = \frac{5}{2} \\ 5x = 15 \times 2 \\ 5x = 30 \\ x = 6$

$5)b) \frac{14}{x} = \frac{2.1}{0.54} \\ 2.1x = 14 \times 0.54 \\ \frac{21x}{10} = 14 \times \frac{54}{100} \\ \frac{21x}{10} = 7 \times \frac{54}{50} \\ \frac{21x}{10} = 7 \times \frac{27}{25} \\ \frac{21x}{10} = \frac{189}{25} \\ 21x \times 25 = 189 \times 10 \\ 525x = 1890 \\ x = \frac{1890}{525} = \frac{378}{125} = 3.6$

$6)c) \frac{25}{6x} = \frac{5}{9} \\ 5 \times 6x = 25 \times 9 \\ 30x = 225 \\ x = \frac{225}{30} = \frac{15}{2} = 7.5$