bonjour
[tex] \sqrt{12} \times \sqrt{30} = \sqrt{4 \times 3} \times \sqrt{30} = 2 \sqrt{3} \times \sqrt{30} = 2 \sqrt{3 \times 30} = 2 \sqrt{3 {}^{2} \times 10 } = 6 \sqrt{10} [/tex]
[tex] \sqrt{7} \times \sqrt{28} \times \sqrt{63} = \sqrt{7} \times \sqrt{4 \times 7} \times \sqrt{9 \times 7} = \sqrt{7} \times 2 \sqrt{7} \times 3 \sqrt{7 } = 7 \times 2 \times 3 \sqrt{7} = 42 \sqrt{7} [/tex]
[tex]5 \sqrt{26} \times \sqrt{2} = 5 \sqrt{26 \times 2} = 5 \sqrt{52} = 5 \sqrt{4 \times 13} = 10 \sqrt{13} [/tex]
[tex] \frac{ \sqrt{480} }{ \sqrt{2 } \times \sqrt{10} } = \frac{ \sqrt{480} }{ \sqrt{20} } = \frac{ \sqrt{20 \times 24} }{ \sqrt{20} } = \sqrt{24} = \sqrt{4 \times 6} = 2 \sqrt{3} [/tex]
bonne continuation
