Explicație pas cu pas:
1.
[tex] \frac{2}{7} = \frac{ {x}^{2} }{56} \\ {x}^{2} = \frac{2 \times 56}{7} \\ {x}^{2} = 2 \times 8 = 16 \\ x = 4[/tex]
2.
[tex]18 = 2 \times {3}^{2} \\ 12 = {2}^{2} \times 3 \\ cmmdc = 2 \times 3 = 6[/tex]
3.
[tex] \frac{40}{65} = \frac{40 \div 5}{65 \div 5} = \frac{8}{13} [/tex]
4. 16% = 16/100 = 4/25
