Question

Aflați x apartine N stiind că a) x/99=2/9 b) 3x+1/15=0,4(6)​

Answer 1

Explicație pas cu pas:

a)

$\dfrac{x}{99} = \dfrac{2}{9} \iff x = \dfrac{2 \cdot 99}{9} \\ x = 2 \cdot 11 \implies x = 22$

b)

$\dfrac{3x + 1}{15} = 0.4(6) \iff \dfrac{3x + 1}{15} = \dfrac{46 - 4}{90} \\ \dfrac{3x + 1}{15} = \dfrac{42}{90} \iff \dfrac{3x + 1}{15} = \dfrac{7}{15} \\ 3x + 1 = 7 \iff 3x = 6 \implies x = 2$