\(\sqrt{2}-8\sqrt{2}+9\sqrt{2}\)
\(=-7\sqrt{2}+9\sqrt{2}=2\sqrt{2}\)
`sqrt{2} - 8sqrt{2} + 9 sqrt{2} `
`= (1 - 8 + 9) sqrt{2}`
`= 2sqrt{2}`
1. Chứng minh:\(\left(\frac{x\sqrt{x}+27y\sqrt{y}}{3\sqrt{x}+9\sqrt{y}}-\sqrt{xy}\right).\left(\frac{3\sqrt{x}+9\sqrt{y}}{9y-x}\right)^2>\sqrt{8}\)
2. Rút gọn A= \(\frac{\sqrt{a+2\sqrt{a-1}}+\sqrt{a-2\sqrt{a-1}}}{\sqrt{a+\sqrt{2a-1}}-\sqrt{a-\sqrt{2a-1}}}\)
Tính
1.\(2\sqrt{4}+4\sqrt{9}+6\sqrt{25}-4\sqrt{16}+\sqrt{0}\)
2. \(2\sqrt{0,09}-7\sqrt{2,25}+8\sqrt{\frac{16}{25}}-\sqrt{1}-0\sqrt{10,1}\)
so sánh \(\sqrt{1}+\sqrt{2}+\sqrt{3}+\sqrt{4}+...+\sqrt{8}+\sqrt{9}và\)\(5\sqrt{5}+12\)
a
\(\sqrt{25-3\sqrt{\frac{4}{3}}}\)
b\(\left(-2^3\right)+\frac{1}{2}:\frac{1}{8}-\sqrt{25}+\left|-64\right|\)
c\(\left(-2^2\right)+\sqrt{36}.2-\sqrt{9}.3+\sqrt{25}\)
\(\sqrt{80}+\sqrt{120}\)và 20
\(\sqrt{2}+\sqrt{6}+\sqrt{30}+\sqrt{90}\)và 19
\(\sqrt{1}+\sqrt{2}+\sqrt{3}+...+\sqrt{8}+\sqrt{9}\)và\(5\sqrt{5}+12\)
Đề bài: So Sánh
Giúp mình giải cũng như cách tính nha
Chứng minh:
\(\sqrt{1}+\sqrt{2}+\sqrt{3}+...+\sqrt{8}+\sqrt{9}< 5\sqrt{5}+12\)
(giải theo cách lớp 7, ko theo phương trình)
a) \(4.\left(-\dfrac{1}{2}\right)^3\)\(-2.\left(-\dfrac{1}{2}\right)^2\)+\(3.\left(-\dfrac{1}{2}\right)\)+1
b) \(8.\sqrt{9}\)\(-\sqrt{64}\)
c) \(\sqrt{\dfrac{9}{16}}\)\(+\dfrac{25}{46}\)\(:\dfrac{5}{23}\)\(-\dfrac{7}{4}\)
đung cho 5 sao
\(\sqrt{2^2+\sqrt{4}^2+\sqrt{-6}^2+\sqrt{-8}^2}\)
Tìm x,tính nhanh:
a.\(2x^2+5x+8+\sqrt{x}=x^2+3x+35+x^2+2x-7.\)
b.\(3\sqrt{x}+7x+5=\sqrt{x}+4x-6+3x+18\)
c.\(8\sqrt{x}+2x-9=5x+7+6\sqrt{x}-3x-12\)
d.\(2\sqrt{3x}+11x-18=5x+3+6\sqrt{3x}+6x-21\)
so sánh \(\sqrt{4+\sqrt{8}}.\sqrt{2+\sqrt{2}+\sqrt{2}}.\sqrt{2-\sqrt{2}+\sqrt{2}}\)với \(\sqrt{3}\)
Cảm ơn
