Salut,
[tex]a).\ \dfrac{a}3=\dfrac{b}7\Rightarrow\dfrac{a}b=\dfrac{3}7.\\\\b).\ \dfrac{a^2}{b^2}=\left(\dfrac{a}b\right)^2=\left(\dfrac{3}7\right)^2=\dfrac{3^2}{7^2}=\dfrac{9}{49}.\\\\c).\ \dfrac{5a}{4b}=\dfrac{5}4\cdot\dfrac{a}b=\dfrac{5}4\cdot\dfrac{3}7=\dfrac{15}{28}.[/tex]
A fost greu ?
Green eyes.
