Tìm x:a,
\(5^x+5^{x+2}=650\)
b,\(4^x+4^{x+3}=4160\)
các bn giúp mk nha
a) \(4^x+4^{x+3}=4160\)
b) \(5^x+5^{x+2}=650\)
a) 4x + 4x + 3 = 4160
4x + 4x . 43 = 4160
4x .( 1 + 43 ) = 4160
4x . 65 = 4160
4x = 4160 : 65
4x = 64 => 4x = 43 => x = 3
b) 5x + 5x + 2 = 650
5x + 5x . 52 = 650
5x . ( 1 + 52 ) = 650
5x . 26 = 650 => 5x = 650 : 26 = 25 => 5x = 52 => x = 2
a) 43 + 43+3 = 4160
b) 52 + 52+2 = 650
Chúc bạn học tốt!
\(a)4^x+4^{x+3}=4160\)
\(\Rightarrow4^x+4^x\cdot4^3=4160\)
\(\Rightarrow4^x+(1\cdot4^3)=4160\)
\(\Rightarrow4^x+(1\cdot64)=4160\)
\(\Rightarrow4^x+64=4160\)
\(\Rightarrow4^x=4160-64\)
\(\Rightarrow4^x=4096\)
\(\Rightarrow4^x=4^6\)
\(\Rightarrow x=6\)
tìm x:a,2 mũ x =16/b,4 mũ x -1=64/c,5 mũ n+5mux n+2=650/d,3<3n<234
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Tìm số tự nhiên x biết
a) \(5^x+5^{x+2}=650\)
b) \(3^{x-1}+5.3^{x-1}=162\)
c) \(4^x+4^{x+3}=4160\)
a)\(5^x+5^{x+2}=650\)(=)\(5x.\left(1+25\right)=650\)(=)\(5^x.26=650\)(=)\(5^x=25\)=>x=2
b)\(3^{x-1}+5.3^{x-1}=162\)(=)\(3^{x-1}.\left(1+5\right)=162\)(=)\(3^{x-1}.6=162\)(=)\(3^{x-1}=27\)(=)\(3^{x-1}=3^3\)=>x-1=3(=)x=2
c)\(4^x+4^{x+3}=4160\)(=)\(4^x.\left(1+64\right)=4160\)(=)\(4^x.65=4160\)(=)\(4^x=64\)(=)\(4^x=4^3\)
=>x=3
học tốt
Bài 4: Tìm x:
a) x + 2/5 = 4/3 b) x : 3/2 = 2 x 1/5
*Bài 5. Viết 3 phân số lớn hơn 1/5 nhưng bé hơn 1/4
`x+2/5=4/3`
`=>x=4/3-2/5`
`=> x= 20/15 -6/15`
`=>x= 14/15`
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`x : 3/2 =2 xx 1/5`
`=> x : 3/2= 2/5`
`=> x= 2/5 xx 3/2`
`=> x= 6/10`
`=>x= 3/5`
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Bài `5` này có `1` chút lạ ạ
Tìm x:
a) x - \(\dfrac{5}{7}\) = \(\dfrac{3}{5}\) x \(\dfrac{1}{2}\) b) x \(x\dfrac{2}{3}=\dfrac{5}{8}+\dfrac{3}{4}\)
\(a,x-\dfrac{5}{7}=\dfrac{3}{5}\times\dfrac{1}{2}\)
\(x-\dfrac{5}{7}=\dfrac{3}{10}\)
\(x=\dfrac{3}{10}+\dfrac{5}{7}\)
\(x=\dfrac{21}{70}+\dfrac{50}{70}\)
\(x=\dfrac{71}{70}\)
\(Vayx=\dfrac{71}{70}\)
\(b,x\times\dfrac{2}{3}=\dfrac{5}{8}+\dfrac{3}{4}\)
\(x\times\dfrac{2}{3}=\dfrac{5}{8}+\dfrac{6}{8}\)
\(x\times\dfrac{2}{3}=\dfrac{11}{8}\)
\(x=\dfrac{11}{8}:\dfrac{2}{3}\)
\(x=\dfrac{11}{8}\times\dfrac{3}{2}\)
\(x=\dfrac{33}{16}\)
\(Vayx=\dfrac{33}{16}\)
Tìm x:
a) 3/4 x X = 5/8
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b) 5/6 - X = 1/ 12
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a)x=\(\dfrac{5}{8}:\dfrac{3}{4}=\dfrac{5}{6}\)
b) x=\(\dfrac{5}{6}-\dfrac{1}{12}=\dfrac{3}{4}\)
a \(x=\dfrac{5}{8}:\dfrac{3}{4}\)
\(x=\dfrac{5}{8}\times\dfrac{4}{3}\)
\(x=\dfrac{5}{6}\)
b \(x=\dfrac{5}{6}-\dfrac{1}{12}\)
\(x=\dfrac{10}{12}-\dfrac{1}{12}\)
\(x=\dfrac{9}{12}\)
\(x=\dfrac{3}{4}\)
tìm số tự nhiên n biết:
a) 4x+4x+3=4160
b) 2x+1+5.xx-2=7/32
Tìm x:
a) x +\(\dfrac{4}{15}\) = \(\dfrac{4}{12}\) b) x - \(\dfrac{5}{8}\) = \(1\dfrac{2}{3}\)
a) \(x+\dfrac{4}{15}=\dfrac{4}{12}\)
\(x=\dfrac{4}{12}-\dfrac{4}{15}\)
\(x=\dfrac{20}{60}-\dfrac{16}{60}\)
\(x=\dfrac{1}{15}\)
b) \(x-\dfrac{5}{8}=1\dfrac{2}{3}\)
\(x-\dfrac{5}{8}=\dfrac{5}{3}\)
\(x=\dfrac{5}{3}+\dfrac{5}{8}\)
\(x=\dfrac{40}{24}+\dfrac{15}{24}\)
\(x=\dfrac{55}{24}\)
Tìm x:
a) X x 3 x 5 = 2,7 b) 1,2 : X x 4 = 20
a: \(x\cdot3\cdot5=2,7\)
=>\(x\cdot15=2,7\)
=>\(x=\dfrac{2,7}{15}=0,18\)
b: \(1,2:x\cdot4=20\)
=>\(1,2:x=20:4=5\)
=>\(x=1,2:5=0,24\)