Question

13 ,14 și la 16 doar subpunctele a și b . Rapid va rog dau funda!!!!

Answer 1

13. a)

x/1 = 3/20
y/1 + z/1 = 1/4

(x+y)+z = ?

tinand cont ca inmultirea e comutativa, putem calcula si x+(y+z). da acelasi raspuns.

$\frac{x}{1} + \frac{y}{1} + \frac{z}{1} = \frac{8}{20} \\ \frac{3}{20} + \frac{1}{4} \\ \frac{3}{20} + \frac{5}{20} \\ = \frac{8}{20}$
b) nu stiu

14. nu mai stiu regula srry

16. a)
$x + 1 \times \frac{2}{3} \: = 3 \times \frac{1}{5} \\ x +\frac{1 \times 3 + 2}{3} = \frac{3 \times 5 + 1}{5} \\ x + \frac{5}{3} = \frac{16}{5} \\ \frac{x}{1} + \frac{5}{3} = \frac{16}{5} \\ \frac{3x}{3} + \frac{5}{3} = \frac{16}{5} \\ \frac{3x + 5}{3} = \frac{16}{5} \\ \frac{15x + 25}{15} = \frac{48}{15}$
=> 15x + 25 = 48
15x = 23
x = 23/15

b)
$2 \times \frac{1}{5} - x = \frac{11}{10} \\ \frac{2 \times 5 + 1}{5} - \frac{x}{1} = \frac{11}{10} \\ \frac{11}{5} - \frac{x}{1} = \frac{11}{10} \\ \frac{11}{5} - \frac{5x}{5} = \frac{11}{10} \\ \frac{11 - 5x}{5} = \frac{11}{10} \\ \frac{22 - 10x}{10} = \frac{11}{10}$
=> 10x = 22-11
10x = 11
x = 11/10