Question

va rog sa ma ajutati

Answer 1

[tex] \it 0,2(7) = \dfrac{27-2}{90} =\dfrac{\ \ 25^{(5}}{90} = \dfrac{5}{18} \\ \\ \\ \dfrac{2a}{9b} = \dfrac{5}{18} \Rightarrow \dfrac{2}{9}\cdot\dfrac{a}{b}=\dfrac{5}{18}\Rightarrow \dfrac{a}{b}=\dfrac{5}{18}\cdot\dfrac{9}{2} \Rightarrow\dfrac{a}{b}=\dfrac{5}{4} \Rightarrow 5b=4a\ \ \ \ \ (*) [/tex]

$\it \dfrac{8a+5b}{9a-5b}\ \stackrel{(*)}{=}\ \dfrac{8a+4a}{9a-4a} = \dfrac{12a}{5a}=\dfrac{12}{5}$