3x.(12x-4)-9x.(4x-3)=30

=> 36x²-12x-36x²+27x=30

=> 15x=30

=> x=30:15

=> x=2

3x(12x-4)-9x(4x-3)=30

<=>36x²-12x-36x²+27x=30

<=>15x=30

<=>x=2

\(3x.\left(12x-4\right)-9x.\left(4x-3\right)=30\)

\(36x^2-12x-36x^2=27x=30\)

\(15x=30\)

\(x=2\)

\(3x\left(12x-4\right)-9x\left(4x-3\right)=30\)

\(\Rightarrow36x^2-12x-36x^2+27x=30\)

\(\Rightarrow\left(36x^2-36x^2\right)+\left(27x-12x\right)=30\)

\(\Rightarrow15x=30\)

\(\Rightarrow x=2\)

\(3x\left(12x-4\right)-9x\left(4x-3\right)=30\)

\(\Rightarrow36x^2-12x-36x^2+27x=30\)

\(\Rightarrow15x=30\Rightarrow x=2\)

Vậy...............

Chúc bạn học tốt!!!

3x(12x – 4) – 9x(4x – 3) = 30

3x.12x – 3x.4 – (9x.4x – 9x.3) = 30

36x2 – 12x – 36x2 + 27x = 30

(36x2 – 36x2) + (27x – 12x) = 30

15x = 30

x = 2

Vậy x = 2.

3x (12x -4 )- 9x (4x-3)= 30 

<=>36x²-12x-36x³+27x=30

<=>15x=30

<=>x=2

\(3x\left(12x-4\right)-9x\left(4x-3\right)=30\)

\(36x^2-12x-36x^2+27x=30\)

\(15x=30\)

\(x=\frac{30}{15}\)

\(x=2\)

= 36X-12X-36X-27X=30

=36X-36X-12X-27X=30

=0-12X-27X

=-12X-27X=30

=X.(-12-27)=30

hình như mình tính sai

nếu công thức đúng thì k nha

\(3x\left(12x-4\right)-9x\left(4x-3\right)=30\)

\(\Leftrightarrow15x=30\)

\(\Leftrightarrow x=2\)

3x(12x+4)-9x(4x-3)=30

=>36.x²+12x-36.x²-27x=30

=>12x-27x=30

=>-15x=30

=>x=30:(-15)

=>x=-2

vậy......

\(3x\left(12x-4\right)-9x\left(4x-3\right)=30\)

=>\(36x^2-12x-36x^2+17x=30\)

=>\(17x-12x=30\)

=>\(5x=30\)

=>x=30:5

=>x=6

\(3.\left(12x-4\right)-9.\left(4x-3\right)=30\)

\(\Rightarrow36x-12-36x+27=30\)

\(\Rightarrow36x-36x=30+12-27\)

\(\Rightarrow x.\left(36-36\right)=15\)

\(\Rightarrow x.0=15\)

\(\Rightarrow x=15:0\) \(???\)

    ĐỀ bài sai rồi 

3x.12x+3x.(-4)-9x.4x-9x.(-3)=30

36x²-12x-36x²-27x=30   

24x-9x=30

15x=30

=>x=30:15

=>x=2

3x(12x-4)-9x(4x-3)=30

3x12x+3x-4-9x4x-9x-3=30

36x^2-12x-36x^2+27x=30

(36^2-36x^2)+(-12x+27x)=30

       0         +     15x     =30

=> 15x=30

Vậy: x=30:15=2