x(100%+20%)=7.2

x120%=720%

x=720%:120%

x=6

vậy////////

(40%+100%)x+20%=720%

140%x=720%-20%

140%x=700%

x=720%:140%

x=36/7

vậy x=/////////////

x﴾100%+20%﴿

=7.2 x120%

=720% x

=720%:120%

x=6 

\(X\times20o/o+X=7,2\)

\(\Leftrightarrow\)2x+0,2=7,2

\(\Leftrightarrow\)2x     =7,2-0,2

\(\Leftrightarrow\)2x     = 7

\(\Rightarrow\) x        =7:2

\(\Rightarrow\)x        =3,5

\(40o/o\times X+X\times20o/o=72\)

\(\Leftrightarrow0,4\times X+X\times0,2=72\)

\(\Leftrightarrow X\times\left(0,4+0,2\right)=72\)

\(\Leftrightarrow X\times0,6=72\)

\(\Rightarrow X=72:0,6\)

\(\Rightarrow X=120\)

40%*x+x*20%=72

-> 0,4x+ 0,2 x= 72

-> 0,6 x= 72

-> x=120

a) X + 20% x X = 7,2

   100% X + 20% x X = 7,2

   ( 100% + 20% ) x X = 7,2

    120% x X = 7,2

                X = 7,2 : 120%

                X = 6

b) X - 20% x X = 216

   100% X - 20% x X = 216

   ( 100% - 20% ) x X = 216

      80% x X = 216

                X = 216 : 80%

                X = 270

x + 20% * x = 7.2

x +1/5 * x = 7.2

x * ( 1 + 1/5 ) = 7.2

x * 1.2 = 7.2

x = 7.2 : 1.2

x = 6

40% * x + x * 20% = 72

2/5 * x + x * 1/5 = 72

( 2/5 + 1/5 ) * x = 72

0.6 * x = 72

x = 72 : 0.6

x = 120

X +\(\frac{1}{5}\)+ X= 7,2

X + X +\(\frac{1}{5}\) =7,2 ( phép cộng có tính chất giao hoán)

X x2 +\(\frac{1}{5}\) =7,2

X x2 =7,2 - \(\frac{1}{5}\)

X x2 =7

X = 7:2

X =3,5

\(x+20\%+x=7,2\)

\(\left(x+x\right)+0,2=7,2\)

\(2x=7,2-0,2\)

\(2x=7\)

\(x=7:2\)

\(x=3,5\)

thanks

x+20%+x=7,2

=> x+x+20%=7,2

=> 2x+0,2    =7,2

=> 2x           =7,2-0,2

=> 2x           =7

=> x             =7:2

=> x             =3,5

Vậy x=3,5

x+20%+x=7,2

=> x+x+20%=7,2

=> 2x+0,2    =7,2

=> 2x           =7,2-0,2

=> 2x           =7

=> x             =7:2

=> x             =3,5

Vậy x=3,5

 **** nha các bạn !!!

X + 20% x X = 7,2

X x 1 + X x 1/5 = 7,2

X x (1 + 1/5) = 7,2

X x 6/5 = 7,2

X = 7,2 : 6/5

X = 7,2 x 5 / 6

X = 6

X + 20%x X=7,2

=> X+ \(\frac{1}{5}\)x X=7,2

=> X x( 1+\(\frac{1}{5}\))=7,2

=> X x \(\frac{6}{5}\)=7,2

=> X=6

thank các bn nha!!! ^_^