Bonsoir,
On sait que [tex]\sqrt{ab} =\sqrt{a}*\sqrt{b}[/tex]
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)
[tex]A = \frac{(\sqrt{7})^{2} *\sqrt{14} }{\sqrt{2} } =\frac{7*\sqrt{14} }{\sqrt{2} } =\frac{7*\sqrt{7*2} }{\sqrt{2} } =\frac{7\sqrt{7} *\sqrt{2} }{\sqrt{2} } =7\sqrt{7}[/tex]
[tex]B = (\sqrt{3}-1)(\sqrt{3} +1)=(\sqrt{3} )^{2} -1^{2} =3-1=2[/tex]
[tex]C=(\sqrt{5} -2)^{2} =(\sqrt{5} )^{2} -2*\sqrt{5} *2+2^{2} =5-4\sqrt{5} +4=9-4\sqrt{5}[/tex]
