Exercice 1 :
1) [tex]D= \dfrac{ \sqrt{500} }{ \sqrt{72}}* \dfrac{ \sqrt{2}}{10}= \dfrac{ \sqrt{500}* \sqrt{2}}{ \sqrt{72}*10}= \dfrac{ \sqrt{1000}}{10 \sqrt{72}}= \dfrac{ \sqrt{10*10^2}}{10 \sqrt{8*3^2}}[/tex]
[tex]= \dfrac{10 \sqrt{10} }{3*10 \sqrt{8} }= \dfrac{10 \sqrt{10} }{30 \sqrt{8} }[/tex]
2) [tex]E=(2 \sqrt{7}-1)^2 +3 \sqrt{28}=(2 \sqrt{7})^2-2*2 \sqrt{7}+1^2+3 \sqrt{7*2^2}} [/tex]
[tex]=28-4 \sqrt{7}+1+6 \sqrt{7}=29 +2 \sqrt{7} [/tex]
On continuera demain......
