\(27+\left(220-6x\right).3=615\)

\(\rightarrow\left(220-6x\right).3=615-27=588\)

\(\rightarrow220-6x=588:3=196\)

\(\rightarrow6x=220-196=24\)

\(\rightarrow x=24:6=4\)

\(315-\left(x-3\right).7=210\)

\(\Rightarrow\left(x-3\right).7=315-210=105\)

\(\Rightarrow x-3=105:7=15\)

\(\Rightarrow x=15+3=18\)

2x - 2³. 3³ = 138

2x - 8 . 27  = 138

2x - 216     = 138

2x              = 138 + 216

2x              = 354

2x              = 354 : 2

 x               = 177

vậy x = 177

( 6x - 3⁴ ) . 7³    = 3 . 7⁴

( 6x - 81 ) . 343  = 3 . 2401

( 6x - 81 ) . 343  = 7203

  6x - 81            = 7203 : 343

  6x - 81            = 21

  6x                   = 21 + 81

  6x                   = 102

    x                   = 102 : 6

    x                   = 17

vậy x = 17

\(2x-2^3.3^2=138\)

\(2x-8.9=138\)

\(2x-72=138\)

\(2x=138+72\)

\(2x=210\)

\(x=210:2\)

\(x=105\)

\(\left(6x-3^4\right).7^3=3.7^4\)

\(\left(6x-3^4\right)=3.7^4:7^3\)

\(\left(6x-3^4\right)=3.7\)

\(6x-81=21\)

\(6x=21+81\)

\(6x=102\)

\(x=102:6\)

\(x=17\)

a) 5(2x -1) - 4(8 - 3x) = 7

<=> 10x - 5 - 32 + 12x = 7

<=> 22x = 44 

<=> x =2

Vậy x = 2 là nghiệm phương trình

b) 7(2x - 5) - 5(7x - 2) + 2(5x - 7) = (x - 2) - (x + 4) 

<=> 14x - 35 - 35x + 10 + 10x - 14 = x - 2 - x - 4

<=> -11x - 39 = - 6

<=> -11x = 33

<=> x = -3

Vậy x = -3 là nghiệm phương trình 

\(a,10x-5-32+12x=7\)

\(22x=44\)

\(x=2\)

\(b,14x-35-35x+10+10x-14=x-2-x-4\)

\(-11x-39=-6\)

\(-11x=-33\)

\(x=3\)

cần ngay bây h