Aplicam proportii derivate.
a) Din [tex] \frac{a}{b}=\frac{3}{d} [/tex] ⇒[tex] \frac{4a+2b}{3a+b}=\frac{4*3+2*2}{3*3+2}=\frac{16}{11} [/tex]
b) [tex] \frac{a^{2}}{b^{2}}=\frac{9}{4} [/tex]
atunci [tex] \frac{a^{2}+2b^{2}}{2a^{2}+b^{2}}=\frac{9+2*4}{2*9+4}=\frac{17}{22} [/tex]
c) [tex] \frac{a^{2}-b^{2}}{6ab}=\frac{9-4}{6*3*2}=\frac{5}{36} [/tex]
