Question

Efectuati
a)√3-√5)²=
b)(2√7+1)=
c)(3-√7)²=
(3√2+2√5)²=

Answer 1

$a).( \sqrt{3} - \sqrt{5} )^2= \sqrt{3} ^ 2-2 \cdot \sqrt{3} \cdot \sqrt{5} + \sqrt{5} ^2=3-2 \sqrt{15} +5=8-2 \sqrt{15} \\ b).(2 \sqrt{7} +1)=(2 \sqrt{7} )^2 +2 \cdot 2 \sqrt{7} \cdot 1+1^2=28+4 \sqrt{7} +1=29+4 \sqrt{7} \\ c).(3- \sqrt{7} )^2=3^2-2\cdot3\cdot \sqrt{7} + \sqrt{7} ^2=9-6 \sqrt{7} +7=16-6 \sqrt{7} \\ d).(3 \sqrt{2} +2 \sqrt{5} )=(3 \sqrt{2} )^2+2 \cdot 3 \sqrt{2} \cdot 2 \sqrt{5} +(2 \sqrt{5} )^2= \\ =18+12 \sqrt{10} +20=38+12 \sqrt{10}$