1)In triunghiul ADC avem [tex] \frac{MD}{MA}= \frac{3}{4} \\ \frac{MD}{MA+MD}= \frac{3}{7} \\ \frac{MD}{AD}= \frac{3}{7} = \frac{NC}{DC} =\ \textgreater \ MN||AC [/tex] (conform reciprocei teoremei lui Thales
2) Ai tastat in plus un [tex]2 \sqrt{2} [/tex] la care renuntam si avem
[tex]a=3 \sqrt{10} +5 \sqrt{10} -12 \sqrt{10} =-4 \sqrt{10} \\ \frac{a}{b}=1 [/tex]