Question

Answer 1

a: =>3/2:|4x-1/5|=7/2-11/4=3/4

=>|4x-1/5|=3/2:3/4=2

=>4x-0,2=2 hoặc 4x-0,2=-2

=>4x=2,2 hoặc 4x=-1,8

=>x=-0,45 hoặc x=0,55

b: =>(2x-15)^3[(2x-15)^2-1]=0

=>(2x-15)^3[(2x-16)(2x-14)]=0

=>\(x\in\left\{\dfrac{15}{2};8;7\right\}\)

c: =>\(\dfrac{315-x}{101}+1+\dfrac{313-x}{103}+1+\dfrac{311-x}{105}+1+\dfrac{309-x}{107}+1=0\)

=>416-x=0

=>x=416

d: =>2(1/6+1/12+...+1/x(x+1))=2015/2017

=>1/2-1/3+1/3-1/4+...+1/x-1/x+1=2015/4034

=>1/2-1/x+1=2015/4034

=>1/x+1=1/2017

=>x+1=2017

=>x=2016