chiu roi

ban oi

minh moi hoc lop 5

tk nhe@@@@@@@@@@@@@

xin do

2x²-5x-7 = (2x-7)(x+1)

chỉ vậy thôi k cho mik nha chúc bn học tốt

a: =>2^4x<2^28

=>4x<28

=>x<7

b: =>5^3x+3<5

=>3x+3<1

=>3x<-2

=>x<-2/3

a) \(16^x< 128^4\)

= (24)^x < (27)⁴

= 2^4x < 2²⁸

= 4x < 28

= x < 7 

Vậy \(x=\left\{0;1;2;3;4;5;6;\right\}\)

\(#Tuyết\)

1/ Ta có: \(5x\left(x-3\right)=\left(x-2\right)\left(5x-1\right)-5\)

\(\Rightarrow5x^2-15x=5x^2-11x+2-5\)

\(\Rightarrow-15x=-11x-3\)

\(\Rightarrow-15x+11x=-3\)

\(\Rightarrow-4x=-3\Rightarrow x=\frac{3}{4}\).

2/ Ta có: \(\left(2x-1\right)\left(x-2\right)-\left(x+3\right)\left(2x-7\right)=3\)

\(\Rightarrow2x^2-5x+2-2x^2+x+21-3=0\)

\(\Rightarrow-4x+20=0\Rightarrow-4x=-20\Rightarrow x=5\).

Chúc bn hc tốt! 

1/ \(5x\left(x-3\right)=\left(x-2\right)\left(5x-1\right)-5\)

<=> \(5x^2-15x=\left(5x^2-x-10x+2\right)-5\)

<=> \(5x^2-15x=5x^2-11x-3\)

<=> \(5x^2-15x-5x^2+11x+3=0\)

<=> \(-4x+3=0\)

<=> \(x=\frac{3}{4}\)

2/ \(\left(2x-1\right)\left(x-2\right)-\left(x+3\right)\left(2x-7\right)=3\)

<=> \(2x^2-4x-x+2-\left(2x^2-7x+6x-21\right)=3\)

<=> \(2x^2-5x+2-2x^2+x+21=3\)

<=> \(-4x+21=3\)

<=> \(4x=17\)

<=> \(x=\frac{17}{4}\)

Cám ơn hai bạn nhiều

=> 1 - 1/6 + 1/6 - 1/11 +.......+1/5x+1 - 1/5x+6=2010/2011

=> 1 - 1/5x+6 = 2010/2011

=> 1/5x+6 = 1/2011

=> 5x + 6 = 2011

=> 5x = 2005

=> x = 401(tm)

\(25< 5x< 3125\\ \Rightarrow5< x< 625\\ \Rightarrow x\in\left\{6;7;8;...;624\right\}\)

`25<5^x<3125`

`->5^2<5^x<5^5`

`->2<x<5`

`->x=3;4`

  1  14-3x=-2+5x

<=>-3x-5x = -2-14

<=> -8x        =-16

<=>        x    =-16/-8=2

mấy bạn ơi...các phương trình trên nó bị lặp lại nhak....ptrinh day ni:

a)\(14-3x=-2+5x\)

b) \(3\times\left(5x+2\right)-x\times\left(5x+2\right)=0\)

c) \(\frac{2x}{3}+\frac{3x-1}{6}=4-\frac{x}{3}\)

d) \(\frac{3-x}{x-2}+\frac{x+1}{x+2}=\frac{3x}{x^2-4}\)

bạn ơi còn nhiều bài nữa ạk