Question

Determinati cifra x astfel incat : x8 cu bara deasupra /x2 cu bara deasupra=8/7.VA ROG! E URGENT
DAU 59 PUNCTE

Answer 1

(10x+8)/(10x+2)=8/7
egalam produsulo mezilor cu al extremilor
70x+56=80x+16
40=10x
4=x
x=4

verificare
48/42=(48:6)/(43:6)=8/7  adevarat , bine rezolvat

Answer 2

[tex]\it \dfrac{\overline{x8}}{\overline{x2}} =\dfrac{8}{7} \Rightarrow \dfrac{8}{7} =\dfrac{\overline{x8}}{\overline{x2}} \Rightarrow \begin{cases}\it 8d= \overline{x8} \\\;\\ 7d=\overline{x2} \end{cases}\Rightarrow 8d-7d= \overline{x8} -\overline{x2} \Rightarrow d=6 \\\;\\ 8\cdot6=48 \\\;\\7\cdot6=42[/tex]

[tex]\it Am \ aflat\ c\breve{a}\ x = 4. \\\;\\ Verificare: \\\;\\ \dfrac{\ 48^{(6}}{42} = \dfrac{8}{7}[/tex]