Bonsoir,

On sait que

2) A = (3√2)² = 3² * (√2)² = 9 * 2 = 18

B = 5 * √(-9)² = 5 * √81 = 5 * 9 = 45

C = √81 / √25 = 9 / 5

D = √20 * √45 = √(4*5) * √(9*5) = √4 * √5 * √9 * √5 = 2√5 * 3√5 = 6 * (√5)² = 6 * 5 = 30

3)

Bonsoir,

1)

A=(3√2)²

A=3²×√2²

A=9×2

A=18

B=5×√(-9)²

B=5×√81

B=5×9

B=45

D=√20×√45

D= √900

D=30

2)

A= √(-7)²×√14/√2

A=√49×√14/√2

A=7×√14/√2

A=7×√7×√2/√2

A=7√7

B=(√3-1)(√3+1)

B=√3×√3+√3*1-1*√3-1*1

B=3+1√3-1√3-1

B=3-1

B=2

C=(√5-2)²

C=√5²-2×√5×2+2²

C=5-4√5+4

C=9-4√5

Bonne soirée !