tim x
2/3 * x = 6/11
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A) 1000000 - 107492 : 154 x 28 + 1000
= 1000000 - 19544 + 1000
= 981456
B) 8/15 + 4/7 + 14/30 + 12/21 + 5
= 15/7 + 5
= 50/7
C) 9/13 : 6/11 - 5/12 : 6/11
= 9/13 x 11/6 - 5/12 x 11/6
= (9/13 - 5/12) x 11/6
= 43/156 x 11/6
= 473/936
Bài 2
1) X x2 + X x 1/5 = 8/5
X x (2 + 1/5 ) = 8/5
X x 11/5 = 8/5
X = 8/5 x 5/11
X = 8/11
2) X : 3/8 = 4/3 : 3/6
X : 3/8 = 8/3
X = 8/3 x 3/8
X = 1
a) 1 000 000 - 107 492 : 154 x 28 + 1000
= 1 000 000 - 698 x 28 + 1000
= 1 000 000 - 19544 + 1000
= 980 456 + 1000
= 981 456
b) 8/15 + 4/7 + 14/30 + 12/21 + 5
= ( 8/15 + 14/30 ) + ( 4/7 + 12/21 ) + 5
= ( 16/30 + 14/30 ) + ( 12/21 + 12/21 ) + 5
= 30/30 + 24/21 + 5
= 1 + 24/21 + 5
= ( 1 + 5 ) + 24/21
= 6 + 24/21
= 150/21
= 50/7
\(A=x^2-2x+50\)
\(A=x^2-2x+1+49\)
\(A=\left(x-1\right)^2+49\ge49\)
Dấu "=" xảy ra khi:
\(x=1\)
\(B=12x-x^2\)
\(B=-x^2+12x\)
\(B=-x^2+12x-36+36\)
\(B=-\left(x^2-12x+36\right)+36\)
\(B=-\left(x-6\right)^2+36\le36\)
Dấu "=" xảy ra khi:
\(x=6\)
\(C=\left(x+1\right)\left(x-2\right)\left(x-3\right)\left(x-6\right)\)
\(C=\left[\left(x+1\right)\left(x-6\right)\right]\left[\left(x-2\right)\left(x-3\right)\right]\)
\(C=\left[x\left(x-6\right)+1\left(x-6\right)\right]\left[x\left(x-3\right)-2\left(x-3\right)\right]\)
\(C=\left(x^2-6x+x-6\right)\left(x^2-3x-2x+6\right)\)
\(C=\left(x^2-5x-6\right)\left(x^2-5x+6\right)\)
\(C=\left(x^2-5x\right)^2-36\ge-36\)
Dấu "=" xảy ra khi:
\(x^2-5x=0\)
\(\Rightarrow x\left(x-5\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x=5\end{matrix}\right.\)
\(\frac{2}{11}x+\frac{3}{10}=\frac{11}{6}-\frac{6}{11}\)
\(\frac{2}{11}x+\frac{3}{10}=\frac{85}{66}\)
\(\frac{2}{11}x=\frac{85}{66}-\frac{3}{10}\)
\(\frac{2}{11}x=\frac{163}{165}\)
\(x=\frac{163}{165}:\frac{2}{11}\)
\(x=\frac{163}{30}\)
1: \(\Leftrightarrow\left(x-1\right)^x\cdot\left(x-1\right)^2-\left(x-1\right)^x=0\)
=>\(\left(x-1\right)^x\cdot\left[\left(x-1\right)^2-1\right]=0\)
=>\(x\left(x-1-1\right)\cdot\left(x-1\right)^x=0\)
=>x(x-2)(x-1)^x=0
=>x=0;x=2;x=1
2: \(\Leftrightarrow\left(6-x\right)^{2003}\left(x-1\right)=0\)
=>6-x=0 hoặc x-1=0
=>x=6;x=1
3: =>(7x-11)^3=32*25+200=1000
=>7x-11=10
=>7x=21
=>x=3
4: =>x^2-1=-3 hoặc x^2-1=3
=>x^2=-2(loại) hoặc x^2=4
=>x=2 hoặc x=-2
a)
6^x.6^3:6^5+81=11^2-4
6^x.6^3:6^5+81=117
6x.63:65=36
6x.63=279936
6x=279936:63
6x=1296
6x=64
x=4
x=6/11:2/3
x=9/11
2/3 . x = 6/11
x = 6/11 : 2/3
x = 9/11