tìm x : x.(1/5+1/4) - ( 1/7+1/8 ) = 0
b 5^2.7^3.11^2+5^2.7^2.11 = 0
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Ta có: 52.73.112.x - 52.72.114 = 0
=> 52.72.112(7x - 112) = 0
=> 7x - 121 = 0
=> 7x = 121
=> x = 121 : 7
=> x = 121/7
ta có \(5^2.7^3.11^2.x+5^3.7^2.11=0< =>5^2.7^2.11\left(77x+1\right)=0\)
<=> \(77x+1=0< =>x=-\frac{1}{77}\)
\(5^2.7^3.11^2.x+5^3.7^2.11=0\)
=>\(5^2.7^2.11.\left(77x+5\right)=0\)
=>\(77x+5=0\)
=>77x=-5
=>\(x=-\dfrac{5}{77}\)
\(5^2.7^3.11^2.x+5^3.7^2.11=0\)
\(5^2.7^2.11.\left(77x+5\right)=0\)
\(77x+5=0\)
\(77x=-5\)
\(x=\dfrac{-5}{77}\)
\(5^2.7^3.11^2.x+5^3.7^2.11=0\)
\(\Leftrightarrow5^2.7^2.11\left(7.11.x+5\right)=0\)
\(\Leftrightarrow77x+5=0\)
\(\Leftrightarrow77x=-5\)
\(\Leftrightarrow x=-\frac{5}{77}\)
( 3x - 24 ) . 75 = 2.76 .1/20170
( 3x - 24 ) . 75 =235298
( 3x - 24 ) = 235298 : 75
( 3x - 24 ) =14
3x = 14 + 24
3x = 30
x = 0
dung 100%
\(\left(3x-2^4\right).7^5=2.7^6.\frac{1}{2017^0}\)
\(\Leftrightarrow\left(3x-16\right).7^5=2.7^6.1\)
\(\Leftrightarrow3x-16=\frac{2.7^6}{7^5}\)
\(\Leftrightarrow3x-16=2.7\)
\(\Leftrightarrow3x-16=14\)
\(\Leftrightarrow3x=30\)
\(\Leftrightarrow x=10\)
1. Tìm x, biết:
a) \(\frac{4}{x}=\frac{8}{6}\). Ta có: \(\frac{8}{6}=\frac{8:2}{6:2}=\frac{4}{3}\Rightarrow x=3\)
b) \(\frac{3}{x-5}=\frac{4}{x+2}\). Ta có: \(5-2=3\)
\(\Rightarrow x=\left(3.5\right)+\left(4.2\right)+3=15+8+3=26\)
c) \(\frac{x}{-2}=\frac{-8}{x}\Rightarrow x=\left(-8\right):\left(-2\right)=4\)
2. Rút gọn
a) \(\frac{2^4.5^2.11^2.7}{2^3.5^3.7^2.11}\Leftrightarrow\frac{2^3.2^1.5^2.11.11.7}{2^3.5^2.5^1.7.7.11}\Leftrightarrow\frac{2^1.11}{5^1.7}=\frac{22}{35}\)
b) Tương tự
c) Tương tự
\(\frac{4}{x}=\frac{8}{6}\Rightarrow x=\frac{4.6}{8}=3\)
\(\frac{3}{x-5}=\frac{-4}{x+2}\Rightarrow3\left(x+2\right)=-4\left(x-5\right)\)
\(\Rightarrow3x+6=-4x+20\)
\(\Rightarrow3x+4x=20-6\)
\(\Rightarrow7x=14\)
\(\Rightarrow x=2\)
\(\frac{x}{-2}=\frac{-8}{x}\Rightarrow x^2=\left(-8\right)\left(-2\right)=16\Rightarrow x=\pm4\)
b/100x+(1+2+3+...+100)=205550
100x+5050=205550
100x=205550-5050
100x=200500
x=200500/100
x=2005
d/(3x-24).75=2.76.1/20090
(3x-24).75=2.76.1
(3x-24)=2.76:75
(3x-24)=2.7
3x-16=14
3x=14+16
3x=30
x=30/10=3