Question

rút gọn biểu thức 

a) \(\sqrt{75}\)+ \(\sqrt{48}\)- \(\sqrt{300}\)

b) \(\sqrt{98}\)- \(\sqrt{72}\)+0,5\(\sqrt{8}\)

c) \(\sqrt{99}\)-\(\sqrt{11}\)+2\(\sqrt{44}\)

Answer 1

Lời giải:
a.

$\sqrt{75}+\sqrt{48}-\sqrt{300}=5\sqrt{3}+4\sqrt{3}-10\sqrt{3}=(5+4-10)\sqrt{3}=-\sqrt{3}$

b.

$\sqrt{98}-\sqrt{72}+0,5\sqrt{8}=7\sqrt{2}-6\sqrt{2}+\sqrt{2}=(7-6+1)\sqrt{2}=2\sqrt{2}$

c.

$\sqrt{99}-\sqrt{11}+2\sqrt{44}=3\sqrt{11}-\sqrt{11}+4\sqrt{11}$

$=(3-1+4)\sqrt{11}=6\sqrt{11}$

Answer 2

\(a\sqrt{75}+\sqrt{48}-\sqrt{300}\)

=\(5\sqrt{3}+4\sqrt{3}-10\sqrt{3}\)

=\(\left(4+5-10\right)\sqrt{3}\)

=-\(\sqrt{3}\)

b\(\sqrt{95}-\sqrt{72}+0,5\sqrt{8}\)

=\(\sqrt{95}-6\sqrt{2}+\sqrt{2}\)

=\(\sqrt{95}-\left(6+1\right)\sqrt{2}\)

=\(\sqrt{95}-7\sqrt{2}\)

c\(\sqrt{99}-\sqrt{11}+2\sqrt{44}\)

=\(3\sqrt{11}-\sqrt{11}+4\sqrt{11}\)

=\(\left(3-1+4\right)\sqrt{11}\)

=\(6\sqrt{11}\)