\(\frac{x}{2}+\frac{x}{2.3}+\frac{x}{3.4}+.....+\frac{x}{2015.2016}=\frac{2015}{4032}\)

\(x.\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+....+\frac{1}{2015.2016}\right)=\frac{2015}{4032}\)

\(x.\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+....+\frac{1}{2015}-\frac{1}{2016}\right)=\frac{2015}{4032}\)

\(x.\left(1-\frac{1}{2016}\right)=\frac{2015}{4032}\)

\(x.\frac{2015}{2016}=\frac{2014}{4032}\)

\(x=\frac{2015}{4032}:\frac{2015}{2016}\)

\(x=\frac{1}{2}\)

\(=\frac{x}{1}-\frac{x}{2}+\frac{x}{2}-\frac{x}{3}+...+\frac{x}{2015}-\frac{x}{2016}=\frac{2015}{4023}\)

\(=\frac{x}{1}-\frac{x}{2016}=\frac{2015}{4023}\)

\(=\frac{2015}{2016}x=\frac{2015}{4023}\)

=> x = \(\frac{2015}{4023}\cdot\frac{2016}{2015}\)= 2016/4023

2x+4x+6x+...+2014x=2015.2016

=>(2+4+6+...+2014).x=2015.2016

tổng trong ngoặc có:(2014-2):2+1=1007(số hạng)

=>tổng= (2014+2).1007:2=1015056

=>1015056.x=4062240

=>x=4030/1007

1,-2015

2,50

3,-2015

thiện xạ 5a3 có thể giải chi tiết ra đc k? Mk cần cách lm

2) 1+2+3+...+x=1275

  Có SSH là: (x+1):1+1=x(SH)

  => (x+1).x:2=1275

=>(x+1).x=1275.2

=>(x+1).x=2550

=>(x+1).x=51.50

=>x=50

3) |x+2015|+|x+2016|=1

Ta thấy  |x+2015| và  |x+2016| > hoặc = 0 với mọi x

=> 1= 0+1=1+0

+) x+2015=0=>x=-2015

     x+2016=1=>x=-2015

+) x+2015=1=>x=-2014

     x+2016=0=> x=-2016

Vậy xE{...}

=> (x+2020)/5=(x+2020)/6=(x+2020)/3+(x+2020)/2

=>(x+2020)(1/5+1/6)=(x+2020)(1/3+1/2)

Với x+2020=0=>x=-2020

Với x+2020 khác 0=>1/5+1/6=1/3+1/2 ,vô lí 

Vậy x=-2020