cho a,b,c>0 và abc=1. CM \(\frac{1}{a^{2010}+b^{2010}+1}+\frac{1}{b^{2010}+c^{2010}+1}+\frac{1}{c^{2010}+a^{2010}+1}\le1\)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
1. \(\frac{3^{10}\cdot11+3^{10}\cdot5}{3^9\cdot2^4}=\frac{3^{10}\left(11+5\right)}{3^9\cdot2^4}=\frac{3^{10}\cdot2^4}{3^9\cdot2^4}=3\)
2. \(\frac{2^{10}\cdot13+2^{10}\cdot65}{2^8\cdot104}=\frac{2^{10}\cdot\left(13+65\right)}{2^8\cdot104}=\frac{2^{10}\cdot78}{2^8\cdot104}=\frac{2^8\cdot2^2\cdot2\cdot3\cdot13}{2^8\cdot2^3\cdot13}=\frac{2^8\cdot2^3\cdot3\cdot13}{2^8\cdot2^3\cdot13}=3\)
3. \(\frac{72^2\cdot54^2}{108^4}=\frac{\left(2^3\cdot3^2\right)^2\cdot\left(2\cdot3^3\right)^2}{\left(2^2\cdot3^3\right)^4}\)
\(=\frac{2^6\cdot3^4\cdot2^2\cdot3^6}{2^8\cdot3^{12}}=\frac{2^8\cdot3^{10}}{2^8\cdot3^{12}}=\frac{3^{10}}{3^{12}}=3^{-2}=\frac{1}{9}\)
4. \(\frac{21^2\cdot14\cdot125}{35^5\cdot6}=\frac{\left(3\cdot7\right)^2\cdot2\cdot7\cdot5^3}{\left(5\cdot7\right)^5\cdot2\cdot3}=\frac{3^2\cdot7^2\cdot2\cdot7\cdot5^3}{5^5\cdot7^5\cdot2\cdot3}=\frac{3^2\cdot7^3\cdot2\cdot5^3}{5^3\cdot5^2\cdot7^2\cdot7^3\cdot2\cdot3}=\frac{3^2}{5^2\cdot3\cdot7^2}=\frac{3}{1225}\)
1. \(\left(-\frac{1}{2}\right)\left(-\frac{1}{2}\right)^4=\left(-\frac{1}{2}\right)^5=-\frac{1}{32}\)
2. \(6.3^2-24:2^3=6.9-24:8=54-3=51\)
3. \(\left(\frac{1}{4}\right)^2.\left(\frac{1}{4}\right)^3=\left(\frac{1}{4}\right)^5=\frac{1}{1024}\)
1) (-1/2).(-1/2)^4 = ( -1/2)^ 5 = -1/32
2) 6.3^2 - 24:2^3 = 6,9 - 24 : 8 = 54 - 3 = 51
3) (1/4)^2 . (1/4)^3 = ( 1/4)^5 = 1/1024
A = -a2 + 3a + 4
A = -( a2 - 3a + 9/4 ) + 25/4
A = -( a - 3/2 )2 + 25/4
-( a - 3/2 )2 ≤ 0 ∀ x => -( a - 3/2 )2 + 25/4 ≤ 25/4
Đẳng thức xảy ra <=> a - 3/2 = 0 => a = 3/2
=> MaxA = 25/4 <=> a = 3/2
\(A=-a^2+3a+4\)
\(\Rightarrow A=-a^2+3a-\frac{9}{4}+\frac{25}{4}\)
\(\Rightarrow A=-\left(a-\frac{3}{2}\right)^2+\frac{25}{4}\)
Vì \(\left(a-\frac{3}{2}\right)^2\ge0\forall a\)\(\Rightarrow-\left(a-\frac{3}{2}\right)^2+\frac{25}{4}\le\frac{25}{4}\)
Dấu "=" xảy ra \(\Leftrightarrow-\left(a-\frac{3}{2}\right)^2=0\Leftrightarrow a-\frac{3}{2}=0\Leftrightarrow a=\frac{3}{2}\)
Vậy maxA = 25/4 <=> a = 3/2
\(\left(9x^2-12x+4\right)-\left(y+2\right)^2\)
\(=\left[\left(3x^2\right)-2.3x.2+2^2\right]-\left(y+2\right)^2\)
\(=\left(3x-2\right)^2-\left(y+2\right)^2\)
\(\left(9x^2-12x+4\right)-\left(y+2\right)^2\)
= \(9x^2-12x+4-\left(y^2+4y+4\right)\)
=\(9x^2-12x+4-y^2-4y-4\)
=\(9x^2-y^2-12x-4y\)
=\(\left(3x-y\right)\left(3x+y\right)-4\left(3x+y\right)\)
=\(\left(3x+y\right)\left(3x-y-4\right)\)
\(8\frac{2}{7}-\left(1\frac{1}{6}+25\%\right)=\frac{58}{7}-\left(\frac{7}{6}+\frac{1}{4}\right)=\frac{58}{7}-\frac{17}{12}=\frac{577}{84}\)
\(4\frac{3}{4}+\left(-0,37\right)+\left(-1,28\right)+\left(-2,5\right)+3\frac{1}{12}\)
\(=\frac{19}{4}+\left(-\frac{83}{20}\right)+\frac{37}{12}=\frac{3}{5}+\frac{37}{12}=\frac{221}{60}\)
\(8\frac{2}{7}-\left(1\frac{1}{6}+25\%\right)=\frac{58}{7}-\left(\frac{7}{6}+\frac{1}{4}\right)=\frac{58}{7}-\frac{17}{12}=\frac{577}{84}\)
\(100+23+x=469\) \(567-x=278-35\) \(x-120=403+60\)
\(123+x=469\) \(567-x=243\) \(x-120=463\)
\(x=469-123\) \(x=567-243\) \(x=463+120\)
\(x=346\) \(x=324\) \(x=583\)
Vậy x = 346 Vậy x = 324 Vậy : x = 583
a) 100+23+x=469
\(\Leftrightarrow123+x=469\)
\(\Leftrightarrow x=469-123\)
\(\Leftrightarrow x=346\)
b) 567-x = 278-35
\(\Leftrightarrow567-x=243\)
\(\Leftrightarrow x=567-243\)
\(\Leftrightarrow x=324\)
Đề bài là gì bạn , chẳng nhẽ tính ?
a) (9x + 1) - (4x + 2) = 9x + 1 - 4x - 2 = (9x - 4x) + (1 - 2) = 5x - 1
b) (3x3 + 1) - (3x2 - 4x + 5) = 3x3 + 1 - 3x2 + 4x - 5 = 3x3 - 3x2 + 4x + (1 - 5) = 3x3 - 3x2 + 4x - 4
a) \(\left(9x+1\right)-\left(4x+2\right)\)
\(=9x+1-4x-2\)
\(=5x-1\)
b) \(\left(3x^2+1\right)-\left(3x^2-4x+5\right)\)
\(=3x^2+1-3x^2+4x-5\)
\(=4x-4\)