Question

Calculati B)3√48-5√3-2√27 e)(√3+2)la patrat -√12 g)(√45-√5)la patrat -20

Answer 1

$a).3 \sqrt{48} -5 \sqrt{3} -2 \sqrt{27} =3 \cdot 4 \sqrt{3} -5 \sqrt{3} -2 \cdot 3 \sqrt{3} = \\ =12 \sqrt{3} -5 \sqrt{3} -6 \sqrt{3} =7 \sqrt{3} -6 \sqrt{3} = \sqrt{3} \\ b).( \sqrt{3} +2)^2- \sqrt{12} = \sqrt{3} ^2+2 \cdot \sqrt{3} \cdot 2+2^2-2 \sqrt{3} = \\ =3+4 \sqrt{3} +4-2 \sqrt{3} =7+2 \sqrt{3} \\ c).( \sqrt{45} - \sqrt{5} )^2-20=(3 \sqrt{5} - \sqrt{5} )^2-20= \\ =(3 \sqrt{5} )^2-2 \cdot 3 \sqrt{5} \cdot \sqrt{5} + \sqrt{5} ^2-20=45-30+5-20=0$