nếu là tìm x thì ta có 2^x+2^x+2^x=53

mà 2^x có thể là cùng chẵn hoặc cùng lẻ 

mà lẻ=lẻ + chẵn hoặc lẻ + lẻ + lẻ 

=> để 2^x là lẻ thì x =0 => 2^x = 1 mà 1+1+1 không bằng 56 => x c { O }

\(\frac{2x-2}{4}=\frac{3y-6}{9}=\frac{-z+3}{-4}=\frac{2x-2+3y-6-z+3}{9}=\frac{56-5}{9}\)\(=\frac{17}{3}\)

\(\Rightarrow x=\frac{37}{3},y=19,z=\frac{77}{3}\)

\(\frac{x-1}{2}=\frac{y-2}{3}=\frac{z-3}{4}\); \(2x+3y-z=56\)

\(\Leftrightarrow\frac{2x-2}{4}=\frac{3y-6}{9}=\frac{z-3}{4};2x+3y-z=56\)

Áp dụng tính chất của dãy tỉ số bằng nhau ta có:

\(\frac{2x-2}{4}=\frac{3y-6}{9}=\frac{z-3}{4}=\frac{2x-2+3y-6-z+3}{4+9-4}=\frac{56-2-6+3}{9}=\frac{51}{9}=\frac{17}{3}\)

\(\Leftrightarrow x=\frac{37}{3};y=19;z=\frac{77}{3}\)

Vậy \(x=\frac{37}{3};y=19;z=\frac{77}{3}\)

56 x ( 4 + 3+ 2 + 1 )

56 x 10

560

=56*4+56*3+56*2+56*1

=56*[4+3+2+1]

=56*10

=560

cho mình xin ít coin nhé

tính nhanh à !

\(a,\Rightarrow x+2=-40\\ \Rightarrow x=-42\\ b,\Rightarrow6x-7-2x=5\\ \Rightarrow4x=12\Rightarrow x=3\\ c,\Rightarrow68-56-x=-2\\ \Rightarrow12-x=-2\\ \Rightarrow x=14\)

Ta có: 2^x + 2^x+1 + 2^x+2 = 56

=> 2^x +  2^x . 2¹ + 2^x . 2² = 56

=> 2^x . 1 +  2^x . 2 + 2^x . 4 = 56

=> 2^x .(1 + 2 + 4) = 56

=> 2^x . 7 = 56

=> 2^x = 56 : 7

=> 2^x  = 8

Mà 8 = 2³ = (-2)³

=> x = 2 hoặc x = -2

Vậy x = 2 hoặc x = -2.

\(\Leftrightarrow2\left(x+1\right)^3=56\Leftrightarrow\left(x+1\right)^3=28\Leftrightarrow\)

\(\left(x+34\right).2=56\)

          \(x+34=56\div2\)

          \(x+34=28\)

                      \(x=28-34\)

                      \(x=-6\)

(x+34) x 2=56

(x+34)=56:2

x+34=28

x=28-34

x=(-6)

\(\left(\frac{2}{11}+\frac{1}{3}\right)\cdot x=\left(\frac{1}{7}-\frac{1}{8}\right)\cdot56\)

\(\Rightarrow\left(\frac{6}{33}+\frac{11}{33}\right)\cdot x=\left(\frac{8}{56}-\frac{7}{56}\right)\cdot56\)

\(\Rightarrow\left(\frac{6+11}{33}\right)\cdot x=\left(\frac{8-7}{56}\right)\cdot56\)

​\(\Rightarrow\frac{17}{33}\cdot x=\frac{1}{56}\cdot56\)​

\(\Rightarrow\frac{17}{33}\cdot x=1\)

\(\Rightarrow x=1:\frac{17}{33}=\frac{33}{17}\)

Vậy x = 33/17

\(\left[\frac{2}{11}+\frac{1}{3}\right]\cdot x=\left[\frac{1}{7}-\frac{1}{8}\right]\cdot56\)

\(\Rightarrow\left[\frac{2\cdot3}{33}+\frac{1\cdot11}{33}\right]\cdot x=\left[\frac{8}{56}-\frac{7}{56}\right]\cdot56\)

\(\Rightarrow\left[\frac{6}{33}+\frac{11}{33}\right]\cdot x=\frac{1}{56}\cdot56\)

\(\Rightarrow\frac{17}{33}\cdot x=1\)

\(\Rightarrow x=1:\frac{17}{33}=1\cdot\frac{33}{17}=\frac{33}{17}\)

Bài 2:a, x+17=109

           x       =109-17

           x        =92

b,x+34=56+42+43

   x+34=141

  x       =141-34

 x        =107

c,2x+45=x+94

 2*x      =x+94-45

 x+x     =x+49

suy ra x=49

d,x+109=1+2+3+........+99

  x+109=495

  x       =495-109

 x        =386

Bài 1 mik ko có làm được.