Question

Daca a , b sunt numere rationale nenule si $\frac{1}{3a}$ = $\frac{2b}{5}$ , Calculati valoarea numarului 12ab-5

Answer 1

$\displaystyle\dfrac{1}{3a}=\dfrac{2b}{5} \\ \\ 6ab=5|\times 2\implies 12ab=10|-5\implies\boxed{12ab-5=5}$

Answer 2

[tex] \frac{1}{3a} = \frac{2b}{5} \,\Leftrightarrow\, \frac{1}{3a}=\frac{^{2)}2b}{5}=\frac{4b}{10}\,\Rightarrow\;10*1=3a*4b\;\\ adica\;12ab=10\;\;|\;-5\;\; \Rghtarrow\;12ab\,-5\,=10-5\;\;deci\;12ab-5=5\,.[/tex]