Question

câu 1 : tính

a,\(\sqrt{121}-2\sqrt{16}\)

b,\(\sqrt{61^2-60^2}\)

c,\(\sqrt{\left(\sqrt{5}-2\right)^2}\)

d,\(2\sqrt{32}+\sqrt{98}-3\sqrt{18}\)

Answer 1

a, \(\sqrt{121}-2\sqrt{16}\)= \(11-8\) = 3

b\(\sqrt{61^2-60^2}\) = \(\sqrt{\left(61+60\right)\left(61-60\right)}\) = \(\sqrt{121.1}\) = 11

c, \(\sqrt{\left(\sqrt{5}-2\right)^2}\) = \(\left|\sqrt{5}-2\right|=\sqrt{5}-2\)

d, \(2\sqrt{32}+\sqrt{98}-3\sqrt{18}=2.4\sqrt{2}+7\sqrt{2}-3.3\sqrt{2}=8\sqrt{2}+7\sqrt{2}-9\sqrt{2}=6\sqrt{2}\)

Answer 2

\(\sqrt{121}-2\sqrt{16}=11-2.4=11-8=3\)

\(\sqrt{61^2-60^2}=\sqrt{\left(61-60\right).\left(61+60\right)}=\sqrt{1.121}=11\)\(\sqrt{\left(\sqrt{5}-2\right)^2}=\sqrt{5}-2\)

\(2\sqrt{32}+\sqrt{98}-3\sqrt{18}=8\sqrt{2}+7\sqrt{2}-9\sqrt{2}=6\sqrt{2}\)