Tính :
B = \(\frac{15-2\sqrt{15}}{\sqrt{15}-2}-\sqrt{18+6\sqrt{5}}\)
Những câu hỏi liên quan
1,826-y/\(1,826-\frac{y^2}{\sqrt{12,04}}:\sqrt{18}\cdot\left(\sqrt{15}-\frac{2,3+\frac{5}{3\sqrt{5}}\cdot7}{0,0598\sqrt{15}+\sqrt[3]{6}}\right)=\frac{7}{4}\)
BT: Tính
a, \(\frac{5\sqrt{60}.3\sqrt{15}}{15\sqrt{50}.2\sqrt{18}}\)
b, \(\sqrt{27\left(\sqrt{3}-\sqrt{5}\right)^2}\)
c, \(\frac{2-\sqrt{3}}{2\sqrt{6}}\)
d, \(\frac{1}{\sqrt{2}+\sqrt{3}}-\frac{3}{\sqrt{2}-\sqrt{3}}\)
thực hiện phép tính:
a)\(\left(\frac{2\sqrt{3}-\sqrt{6}}{\sqrt{8}-2}-\frac{\sqrt{216}}{3}\right).\frac{1}{\sqrt{6}}\)
b)\(\left(\frac{\sqrt{14}-\sqrt{7}}{1-\sqrt{2}}+\frac{\sqrt{15}-\sqrt{5}}{1-\sqrt{3}}\right):\frac{1}{\sqrt{7}-\sqrt{5}}\)
c)\(\frac{\sqrt{5-2\sqrt{6}}+\sqrt{8-2\sqrt{15}}}{\sqrt{7+2\sqrt{10}}}\)
a) Kết quả rút gọn xấu (+dài) nữa. (có thể đề sai)
b)
\(\left(\frac{\sqrt{14}-\sqrt{7}}{1-\sqrt{2}}+\frac{\sqrt{15}-\sqrt{5}}{1-\sqrt{3}}\right):\frac{1}{\sqrt{7}-\sqrt{5}}\)
\(=\left[\frac{-\sqrt{7}\left(1-\sqrt{2}\right)}{1-\sqrt{2}}+\frac{-\sqrt{5}\left(1-\sqrt{3}\right)}{1-\sqrt{3}}\right].\left(\sqrt{7}-\sqrt{5}\right)\)
\(=-\left(\sqrt{7}+\sqrt{5}\right)\left(\sqrt{7}-\sqrt{5}\right)=-\left(7-5\right)=-2\)
c) \(\frac{\sqrt{5-2\sqrt{6}}+\sqrt{8-2\sqrt{15}}}{\sqrt{7+2\sqrt{10}}}=\frac{\sqrt{\left(\sqrt{3}-\sqrt{2}\right)^2}+\sqrt{\left(\sqrt{5}-\sqrt{3}\right)^2}}{\sqrt{\left(\sqrt{5}+\sqrt{2}\right)^2}}\)
\(=\frac{\sqrt{3}-\sqrt{2}+\sqrt{5}-\sqrt{3}}{\sqrt{5}+\sqrt{2}}=\frac{\sqrt{5}-\sqrt{2}}{\sqrt{5}+\sqrt{2}}=\frac{\left(\sqrt{5}-\sqrt{2}\right)^2}{3}\)
Đúng 0
Bình luận (0)
a) \(\left(\frac{2\sqrt{3}-\sqrt{6}}{\sqrt{8}-2}-\frac{\sqrt{216}}{3}\right).\frac{1}{\sqrt{6}}=\left[\frac{\sqrt{6}\left(\sqrt{2}-1\right)}{2\left(\sqrt{2}-1\right)}-2\sqrt{6}\right].\frac{1}{\sqrt{6}}\)
\(=\left(\frac{\sqrt{6}}{2}-2\sqrt{6}\right).\frac{1}{\sqrt{6}}=\frac{1}{2}-2=-\frac{3}{2}\)
Đúng 0
Bình luận (0)
BT: Tính
a, \(\frac{5\sqrt{60}.3\sqrt{15}}{15\sqrt{60}.2\sqrt{18}}\)
b, \(\sqrt{27\left(\sqrt{3}-\sqrt{5}\right)^2}\)
c, \(\frac{2-\sqrt{3}}{2\sqrt{6}}\)
d, \(\frac{1}{\sqrt{2}+\sqrt{3}}-\frac{3}{\sqrt{2}-\sqrt{3}}\)
BT: Tính
a, \(\frac{5\sqrt{60}.3\sqrt{15}}{15\sqrt{50}.2\sqrt{18}}\)
b, \(\sqrt{27\left(\sqrt{3}-\sqrt{5}\right)^2}\)
c, \(\frac{2-\sqrt{3}}{2\sqrt{6}}\)
d, \(\frac{1}{\sqrt{2}+\sqrt{3}}-\frac{3}{\sqrt{2}-\sqrt{3}}\)
Câu 1: Thực hiện phép tính
a,left(sqrt{12}+3sqrt{15}-4sqrt{135}right)cdotsqrt{3}
b,sqrt{252}-sqrt{700}+sqrt{1008}-sqrt{448}
c,2sqrt{40sqrt{12}}-2sqrt{sqrt{75}}-3sqrt{5sqrt{48}}
Câu 2: Rút gọn
a,frac{9sqrt{5}+3sqrt{27}}{sqrt{5}+sqrt{3}}
b,frac{3sqrt{8}+2sqrt{12}+sqrt{20}}{3sqrt{18}-2sqrt{27}+sqrt{45}}
c,left(4+sqrt{15}right)cdotleft(sqrt{10}-sqrt{6}right)cdotsqrt{4-sqrt{15}}
Câu 3:So sánh
a,3+sqrt{5}và2sqrt{2}+sqrt{6}
b,2sqrt{3}+4và3sqrt{2}+sqrt{10}
c,18vàsqrt{15}cdotsqrt{17}
Đọc tiếp
Câu 1: Thực hiện phép tính
\(a,\left(\sqrt{12}+3\sqrt{15}-4\sqrt{135}\right)\cdot\sqrt{3}\\ b,\sqrt{252}-\sqrt{700}+\sqrt{1008}-\sqrt{448}\\ c,2\sqrt{40\sqrt{12}}-2\sqrt{\sqrt{75}}-3\sqrt{5\sqrt{48}}\)
Câu 2: Rút gọn
\(a,\frac{9\sqrt{5}+3\sqrt{27}}{\sqrt{5}+\sqrt{3}}\\ b,\frac{3\sqrt{8}+2\sqrt{12}+\sqrt{20}}{3\sqrt{18}-2\sqrt{27}+\sqrt{45}}\\ c,\left(4+\sqrt{15}\right)\cdot\left(\sqrt{10}-\sqrt{6}\right)\cdot\sqrt{4-\sqrt{15}}\)
Câu 3:So sánh
\(a,3+\sqrt{5}và2\sqrt{2}+\sqrt{6}\\ b,2\sqrt{3}+4và3\sqrt{2}+\sqrt{10}\\ c,18và\sqrt{15}\cdot\sqrt{17}\)
Rút gọn\(B=\frac{3\sqrt{8}+2\sqrt{12}+\sqrt{20}}{3\sqrt{18}-2\sqrt{27}+\sqrt{45}}\\ C=\left(4+\sqrt{15}\right)\left(\sqrt{10}-\sqrt{6}\right)\sqrt{4-\sqrt{15}}\)
29 tháng 7 2020 lúc 8:35
Rút gọn
\(\sqrt{9-\sqrt{17}}.\sqrt{9+\sqrt{18}}\)
\(\left(\frac{1}{5-2\sqrt{6}}+\frac{2}{5+2\sqrt{6}}\right).\left(15+2\sqrt{6}\right)\)
b) Ta có: \(\left(\frac{1}{5-2\sqrt{6}}+\frac{2}{5+2\sqrt{6}}\right)\cdot\left(15+2\sqrt{6}\right)\)
\(=\left(\frac{5+2\sqrt{6}+2\left(5-2\sqrt{6}\right)}{\left(5-2\sqrt{6}\right)\left(5+2\sqrt{6}\right)}\right)\cdot\left(15+2\sqrt{6}\right)\)
\(=\frac{5+2\sqrt{6}+10-4\sqrt{6}}{25-24}\cdot\left(15+2\sqrt{6}\right)\)
\(=\left(15-2\sqrt{6}\right)\cdot\left(15+2\sqrt{6}\right)\)
\(=15^2-\left(2\sqrt{6}\right)^2\)
\(=225-24=201\)
Đúng 0
Bình luận (0)
Tính
\(\frac{\sqrt{15}-\sqrt{12}}{\sqrt{5}-2}+\frac{6+2\sqrt{6}}{\sqrt{3}+\sqrt{2}}\)
\(\frac{\sqrt{15}-\sqrt{12}}{\sqrt{5}-2}\)+\(\frac{6+2\sqrt{6}}{\sqrt{3}+\sqrt{2}}\)\(=\frac{\sqrt{3}\left(\sqrt{5}-2\right)}{\sqrt{5}-2}\)+\(\frac{2\sqrt{3}\left(\sqrt{3}+\sqrt{3}\right)}{\sqrt{3}+\sqrt{2}}\)\(=\sqrt{3}+2\sqrt{3}\)=\(3\sqrt{3}.\)
Đúng 0
Bình luận (0)