Question

Determinati x astfel incat fiecare din urmatoarele fractii sa fie egala cu fractia 3 supra 7

a) X supra 28 b) 45 supra X c 2X+1 supra 21

Answer 1

$a) \frac{x}{28} = \frac{3}{7} =\ \textgreater \ x= \frac{28*3}{7} =12$

$b) \frac{45}{x} = \frac{3}{7} =\ \textgreater \ x= \frac{45*7}{3} =105$

$c) \frac{2x+1}{21} = \frac{3}{7} =\ \textgreater \ 7(2x+1)=21*3;14x+7=63=\ \textgreater \ 14x=56$ =>x=4