bjr
a) √2 x √6
comment procéder
on décompose √6 : √6 = √(2 x 3) = √2 x √3
puis on associe les deux facteurs √2 [√2 x √2 = 2]
√2 x √6 = √2 x √2 x √3 = (√2 x √2) x √3
= 2 √3
b) √3 x √6 = √3 x √2 x√3 = √3 x √3 x √2
= (√3 x √3) √2
= 3√2
c) √7 x 3√14 = √7 x 3 x √(2 x 7)
= √7 x 3 x √2 x √7
= 3 x √2 x √7 x √7
= 3 x (√7 x √7) x √2
= 3 x 7 x √2
= 21√2
d)
7√2 x 5√70 = 7√2 x 5 x √(7 x 2 x 5)
= 7√2 x 5 x √7 x √2 x √5
= 7 x √2 x √2 x 5 x√7 x √5
= 7 x 2 x 5 x √35
= 70√35
