Ta có:(2x-5)³=8

=>(2x-5)³=2³

=>2x-5=2

=>2x=2+5

=>2x=7

=>x=7:2

=>x=3,5

-(x+4)+(12+x)=2.x+12

=> -x-4+12+x=2.x+12

=> 8=2.x+12

=> 2.x+12=8

=> 2.x=-4

=> x=-4:2

=> x=-2

Bài làm

5.2^2x+1 + 2^2x+3 = 288

<=> 5.2^2x.2 + 2^2x.2³ = 288

<=> 10.2^2x + 2^2x.8 = 288

<=> 2^2x( 10 + 8 ) = 288

<=> 2^2x.18 = 288

<=> 2^2x = 16

<=> 2^2x = 2⁴

<=> 2x = 4

<=> x = 2

Vậy x = 2

5(x+4)-3(x-2)=x

=>2(x+13)=x

=>2x+26=x

=>x-2x=26

=>-x=26

=>x=-26

5(x+4)-3(x-2)=x

\(\Leftrightarrow5x+20-3x+6=x\)

\(\Leftrightarrow2x+26=x\)

\(\Leftrightarrow2x-x=-26\)

\(x=-26\)

x - 30 : 6 = 8 x 9 

x - 5 = 72

    x  = 72 + 5 

   x   = 77

Vậy x = 77

Có x+10=|x|-10

     =>x=|x|-20

     =>x<|x|

Suy ra x là số âm

Nên |x|=-x

     =>x+10=-x-10

     =>x+10=-(x+10)

Nên x+10=0

     =>x=-10

Vậy x=-10

\(a,x-1⋮x-3\)

\(\Rightarrow x-3+2⋮x-3\)

\(\Rightarrow2⋮x-3\)

\(x-3=\left\{-2;-1;1;2\right\}\)

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

\(b,x+6⋮x-1\)

\(\Rightarrow x-1+7⋮x-1\)

\(\Rightarrow7⋮x-1\)

\(x=\left\{-6;0;2;8\right\}\)

\(c,x⋮x-5\)

\(x-5+5⋮x-5\)

\(5⋮x-5\)

\(x=\left\{0;4;6;11\right\}\)

Xét x>5:

\(\Rightarrow\)x-3=x+5

\(\Rightarrow\)-3=5(vô lí)

Xét 3<x<5:

\(\Rightarrow\)x-3=5-x

\(\Rightarrow\)x=4(thỏa mãn)

Xét x<3:

\(\Rightarrow\)3-x=5-x

\(\Rightarrow\)3=5(vô lí)

Vậy x=4