Question

Tìm x biết: 3.(x +3 )=12.(6 -x) +12

Answer 1

3x + 9 = 72 - 12x + 12

3x + 12x = 72 + 12 - 9

15x       = 75

x            = 75 : 15

x            = 5

Answer 2

\(3\left(x+3\right)=12\left(6-x\right)+12\)

\(3x+9=72-12x+12\)

\(3x+12x=72+12-9\)

\(15x=75\)

\(x=5\)

=.= hok tốt !!

Answer 3

\(3\left(x+3\right)=12\left(6-x\right)+12\)

\(3x+9=72-12x+12\)

\(3x+12x=72+12-9\)

\(15x=75\)

\(x=5\)

Answer 4

3( x + 3 ) = 12( 6 - x ) + 12

3x + 9 = 72 - 12x + 12

3x + 12x = 72 - 9 + 12

15x = 72

x = 72 : 15

x = 24/5

Answer 5

\(3\left(x+3\right)=12\left(6-x\right)+12\)

\(3x+9=-12x+84\)

\(3x+9-9=-12x+84-9\)

\(3x=-12x+75\)

\(3x+12x=-12+75+12x\)

\(15x=75\)

\(x=5\)

Answer 6

3.(x + 3) = 12.(6 - x) + 12

<=> 3.( x +3) = 12.( 7 - x)

<=> ( x + 3) : ( 7 - x) = 12 :3

<=> \(\frac{x}{7}-\frac{x}{x}+\frac{3}{7}-\frac{3}{x}=\)\(4\)

<=> \(\frac{x}{7}-\frac{3}{x}=\)\(4+1-\frac{3}{7}\)

<=> \(\frac{x^2-21}{7.x}\) \(=\frac{32}{7}\)

<=> x² -21 = \(\frac{32}{7}.7.x\)

<=>  x² -21 = 32.x

<=> x² - 32.x = 21

<=> x ( 32 - x) = 21 = 3.7 = 7.3 = 1 . 21 = 21.1

Bạn lập bảng rồi thay x vào nha...có gì  không hiểu thì nt hỏi mik

Answer 7

\(3x+9=72-12x+12\)

\(3x=84-12x-9\)

\(3x=75-12x\)

\(3x+12x=75\)

\(15x=75\)

\(x=5\)