Question

Va rog este urgent ofer 18 de puncte ​

Answer 1

1)

$\it \dfrac{8}{15}<\dfrac{n}{12}<\dfrac{7}{10}|_{\cdot60} \Rightarrow 32<5n<42|_{:5}\Rightarrow 6,4<n<8,4\Rightarrow n\in\{7,\ \ 8\}$

2)

$\it x+12,5=3,5x|_{\cdot2}\Rightarrow 2x+25=7x\Rightarrow 25=7x-2x\Rightarrow 25=5x\Rightarrow x=5$

Answer 2

Răspuns:

{7 ;8}

5∈N

Explicație pas cu pas:

32/60<5n/60<42/60

n=7 sau 8, pt ca 5*7=35 si 5*8=40

...x+12,5=3,5 x...

2,5x=12,5

n=5 , natural