X x 3/5+ Xx 3/7=31/70

=>X x (3/5+3/7)=31/70

=>X x 36/35=31/70

=>X=31/70:36/35

=>X=31/72

X x 3/5+ Xx 3/7=31/70

=>X x (3/5+3/7)=31/70

=>X x 36/35=31/70

=>X=31/70:36/35

=>X=31/72

X x 3/5+ Xx 3/7=31/70

=>X x (3/5+3/7)=31/70

=>X x 36/35=31/70

=>X=31/70:36/35

=>X=31/72

x+1000-200=2000

x+1000=2200

x=2200-1000

x=1200

70-5.(x-3)=45

5.(x-3)=70-45

5.(x-3)=25

x-3=5

x=8

x+1 000 - 200 = 2 000 

x + 1000=2200

x=1200

vậy x=1200.

70-5.(x-3)=45

5.(x-3)=25

x-3=5

x=8.

vậy x=8.

x + 1000 - 200 = 2000

x + 1000 = 2000 + 200

x + 1000 = 2200

          x = 2200 - 1000

          x = 1200

70 - 5.(x - 3) = 45

       5.(x - 3) = 70 - 45

       5.(x - 3) = 25

           x - 3 = 25 : 5 

           x - 3 = 5

                x = 5 + 3

                x = 8

70:4x + 720/x = 1/2

=> 70/4x + 2880/4x = 1/2

=> 2950/4x = 1/2

=> x = 1475

sai rồi làm lại ha

2*-1.7-70 %=-3.4-70%

-3.4-70/100=-4.1

100% luôn

2 . ( -1,7 ) - 70 %

= - 3,4 - 0,7

=      -4,1 

k mình nha 

2*x-70

2*(-1.7)-70=-3.4-70

=-73.4

a)x=1

b)x=8

k mk nah 

mk k lại cho!

a. 12 . (x - 1) = 0

=> x - 1 = 0 : 12

=> x - 1 = 0

=> x = 0 + 1

=> x = 1.

b/ 70 - 5(x - 3) = 45

=> 5(x - 3) = 70 - 45

=> 5(x - 3) = 25

=> x - 3 = 25 :5

=> x - 3 = 5

=> x = 5 + 3

=> x = 8

X-1=12x0

X-1=0

X=0+1

x=1

b) 5x(X-3)=70-45

5x(X-3)=25

X-3=25:5

X-3=5

X=5+3

X=8

a)\(\frac{72-x}{7}=\frac{x-70}{9}\)

<=>\(\frac{\left(72-x\right).9}{63}=\frac{\left(x-70\right).7}{63}\)

=>\(\frac{648-9x-7x+490}{63}=0\)

<=>.\(\frac{-16x+1138}{63}=0\)

<=>-16x+1138=0

<=>x=71,125

b)\(\frac{x-1}{x+2}=\frac{x-2}{x+3}\)

<=>\(\left(x-1\right)\left(x+3\right)=\left(x+2\right)\left(x-2\right)\)

<=>\(x^2+3x-x-3=x^2-4\)

<=>\(2x=-4+3\)

<=>\(2x=-1\)

<=>x=-0,5