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13 tháng 8 2019

Đề là j?

13 tháng 8 2019

\(16^{x-1}=32^{2x-1}\)

\(\left(2^4\right)^{x-1}=\left(2^5\right)^{2x-1}\)

\(2^{4.x-4}=2^{10x-5}\)

\(4.x-4=10x-5\)

\(4x-10x=-4-5\)

\(4x-10x=-9\)

\(x.\left(4-10\right)=-9\)

\(x.-6=-9\)

\(x=-6.-9\)

\(x=54\)

20 tháng 9 2023

\(\left(2x+1\right)^3=125\\ \Rightarrow\left(2x+1\right)^3=5^3\\ \Rightarrow2x+1=5\\ \Rightarrow2x=4\\ \Rightarrow x=2.\\ b,\left(2x-1\right)^4=16\\ \Rightarrow\left(2x-1\right)^4=2^4\\ \Rightarrow2x-1=2\\ \Rightarrow2x=3\\ \Rightarrow x=\dfrac{3}{2}.\\ c,6.3^x-2.3^x=36\\ \Rightarrow3^x.\left(6-2\right)=36\\ \Rightarrow3^x.4=36\\ \Rightarrow3^x=9\\ \Rightarrow3^x=3^2\\ \Rightarrow x=2.\\ d,2^{x+1}-2^x=32\\ \Rightarrow2^x.\left(2-1\right)=32\\ \Rightarrow2^x=2^5\\ \Rightarrow x=5.\)

17 tháng 9 2023

Vậy \(( - 32{x^5} + 1):( - 2x + 1) = 16{x^4} + 8{x^3} + 4{x^2} + 2x + 1\).

13 tháng 12 2022

a.1+3+5+7+...+2x+1=225

[(2x+1-1):2+1]x(2x+1+1):2=225

(x+1)x(2x+2):2=225

(x+1)x(x+1)=225

(x+1)2=225

(x+1)2=152

x+1=15

x=14

_______________

b. 130-[5.(9-x)+43]=47

    5.(9-x)+43=83

  5.(9-x)=40

9-x=8

x=1

_______________

c.16x<324

24x<220

=>x∈{0;1;2;3;4}

13 tháng 12 2022

a: =>(x+1)^2=225

=>x+1=15

=>x=14

b: =>[5*(9-x)+43]=130-47=83

=>5(9-x)=40

=>9-x=8

=>x=1

c: =>2^4x<2^20

=>4x<20

=>0<x<5

8 tháng 8 2017

\(\dfrac{2x}{15}+\dfrac{2x}{35}+\dfrac{2x}{63}+...+\dfrac{2x}{195}=\dfrac{4}{5}\\ x\cdot\left(\dfrac{2}{15}+\dfrac{2}{35}+\dfrac{2}{63}+...+\dfrac{2}{195}\right)=\dfrac{4}{5}\\ x\cdot\left(\dfrac{2}{3\cdot5}+\dfrac{2}{5\cdot7}+\dfrac{2}{7\cdot9}+...+\dfrac{2}{13\cdot15}\right)=\dfrac{4}{5}\\ x\cdot\left(\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{9}+...+\dfrac{1}{13}-\dfrac{1}{15}\right)=\dfrac{4}{5}\\ x\cdot\left(\dfrac{1}{3}-\dfrac{1}{15}\right)=\dfrac{4}{5}\\ x\cdot\dfrac{4}{15}=\dfrac{4}{5}\\ x=\dfrac{4}{5}:\dfrac{4}{15}\\ x=3\)

Gọi \(D=\dfrac{1}{2}-\dfrac{1}{4}+\dfrac{1}{8}-\dfrac{1}{16}+\dfrac{1}{32}-\dfrac{1}{64}\)

\(2D=1-\dfrac{1}{2}+\dfrac{1}{4}-\dfrac{1}{8}+\dfrac{1}{16}-\dfrac{1}{32}\\ 2D+D=\left(1-\dfrac{1}{2}+\dfrac{1}{4}-\dfrac{1}{8}+\dfrac{1}{16}-\dfrac{1}{32}\right)+\left(\dfrac{1}{2}-\dfrac{1}{4}+\dfrac{1}{8}-\dfrac{1}{16}+\dfrac{1}{32}-\dfrac{1}{64}\right)\\ 3D=1-\dfrac{1}{2}+\dfrac{1}{4}-\dfrac{1}{8}+\dfrac{1}{16}-\dfrac{1}{32}+\dfrac{1}{2}-\dfrac{1}{4}+\dfrac{1}{8}-\dfrac{1}{16}+\dfrac{1}{32}-\dfrac{1}{64}\\ 3D=1-\dfrac{1}{64}< 1\\ \Rightarrow D=\dfrac{1-\dfrac{1}{64}}{3}< \dfrac{1}{3}\)

Vậy \(\dfrac{1}{2}-\dfrac{1}{4}+\dfrac{1}{8}-\dfrac{1}{16}+\dfrac{1}{32}-\dfrac{1}{64}< \dfrac{1}{3}\)

22 tháng 10 2021

3: \(x^3+3x^2-16x-48\)

\(=x^2\left(x+3\right)-16\left(x+3\right)\)

\(=\left(x+3\right)\left(x-4\right)\left(x+4\right)\)

22 tháng 10 2021

làm hết giúp mình với!

 

a: \(\dfrac{96}{\left(x-4\right)\left(x+4\right)}+\dfrac{7+x}{4-x}=\dfrac{2x-1}{x+4}-3\)

\(\Leftrightarrow\dfrac{96}{\left(x-4\right)\left(x+4\right)}-\dfrac{\left(x+7\right)\left(x+4\right)}{\left(x-4\right)\left(x+4\right)}=\dfrac{\left(2x-1\right)\left(x-4\right)}{\left(x+4\right)\left(x-4\right)}-\dfrac{3\left(x-4\right)\left(x+4\right)}{\left(x-4\right)\left(x+4\right)}\)

Suy ra: \(96-x^2-11x-28=2x^2-9x+4-3\left(x^2-16\right)\)

\(\Leftrightarrow-x^2-11x+68=2x^2-9x+4-3x^2+48\)

\(\Leftrightarrow-x^2-11x+68=-x^2-9x+52\)

=>-11x+68=-9x+52

=>-2x=-16

hay x=8(nhận)

b: \(\dfrac{2}{x-1}+\dfrac{3}{x-2}=\dfrac{3}{x-3}\)

\(\Leftrightarrow2\left(x-2\right)\left(x-3\right)+3\left(x-1\right)\left(x-3\right)=3\left(x-1\right)\left(x-2\right)\)

\(\Leftrightarrow2\left(x^2-5x+6\right)+3\left(x^2-4x+3\right)=3\left(x^2-3x+2\right)\)

\(\Leftrightarrow2x^2-10x+12+3x^2-12x+9=3x^2-9x+6\)

\(\Leftrightarrow5x^2-22x+21-3x^2+9x-6=0\)

\(\Leftrightarrow2x^2-13x+15=0\)

\(\Leftrightarrow2x^2-10x-3x+15=0\)

=>(x-5)(2x-3)=0

=>x=5(nhận) hoặc x=3/2(nhận)