=3/4.0,25+3/4.1,25-3/4.0,5

=3/4.(0,25+1,25-0,5)

=3/4.10

=15/2

`3/4.0,25+3/4.1,25-3/4.0,5`

`=3/4.(0,25+1,25-0,5)`

`=3/4xx10=15/2`

=3/4x(0,25+1,25-0,5)=3/4x10=15/2

1) 2,75 - 5/6 × 2/5 = 2,75 - (5/6) × (2/5) = 2,75 - 1/3 = 2,75 - 0,33 = 2,42

2) 1,25 - (5/6 - 0,75) - 3/5 = 1,25 - (5/6 - 0,75) - 3/5 = 1,25 - (5/6 - 3/4) - 3/5 = 1,25 - (5/6 - 9/12) - 3/5 = 1,25 - (10/12 - 9/12) - 3/5 = 1,25 - 1/12 - 3/5 = 1,25 - 0,08 - 0,6 = 1,25 - 0,68 = 0,57

3) 4/9 × 0,75 + 8/5 + 3,125 = (4/9) × 0,75 + 8/5 + 3,125 = 0,44 + 8/5 + 3,125 = 0,44 + 1,6 + 3,125 = 0,44 + 4,725 = 5,165

4) 1,125 - 4/7 - 0,12 = 1,125 - (4/7) - 0,12 = 1,125 - 0,57 - 0,12 = 0,435 - 0,12 = 0,315

5) (1/3 + 0,4) × 3,5 + (1/6 + 0,75) × 6/5

8,75 x X + 0,75 + 1,25 x X + 0,25 = 20 + 0,25 + 0,75

8,75 x X + 0,75 + 1,25 x X + 0,25 = 20 + 1

8,75 x X + 0,75 + 1,25 x X + 0,25 = 21

( 8,75 + 1,25 ) x X + ( 0,75 + 0,25) = 21

10 x X + 1 = 21

10 x X       = 21 - 1

10 x X       = 20

       X       =  20 : 10

       X       = 2

tk nha

8,75x X+0,75+1,25x X +0,25=20+1/4+0,75

8,75x X +0,75+1,25x X +0,25=21

(8,75+0,25)xX+0,75=21

9xX+0,75=21

9xX=21-0,75

9xX=20,25

X=20,25:9

X=2,25

mk nhanh nhất tk nha

8,75 x X + 0.75 +1,25 x X + 0,25 = 20 + 1/4 + 0,75

=> 8,75x + 0,75 + 1,25x + 0,25 = 20 + 1/4 + 0,75

=> 8,75x + 1,25x = 20 

=> 10x = 20

=> x = 2

Vậy x là 2

a) ( x + 0,75 ) : 1,25 = 6

    (  x + 0,75 )            = 6 x 1,25

      x + 0,75             = 7,5

              x                = 7,5 - 0,75

              x                = 6,75.

Bạn ơi phần b) sai hả? 2 làm sao trừ được 4,7!

a)6,75

=136,78*1-136,78*1+136,78*1

=136,78

Thay X \(=1,25\) vào biểu thức \(\dfrac{4}{7}\) x \(X+\dfrac{3}{7}-0,75\) x X ta có:

 \(\dfrac{4}{7}\) x \(1,25+\dfrac{3}{7}-0,75\) x \(1,25\)

\(=\dfrac{5}{7}+\dfrac{3}{7}-\dfrac{15}{16}\)

\(=\dfrac{80}{112}+\dfrac{48}{112}-\dfrac{105}{112}\)

\(=\dfrac{80+48-105}{112}=\dfrac{23}{112}\)

Vậy X\(=1,25\) giá trị biểu thức  \(\dfrac{4}{7}\) x \(X+\dfrac{3}{7}-0,75\) x X là: \(\dfrac{23}{112}\)

1/2.x-2/3+0,75=1,25.2/3

1/2.x-2/3+3/4=5/4.2/3

1/2.x-2/3+3/4=5/6

1/2.x-2/3=5/6-3/4

1/2.x-2/3=1/12

1/2.x=1/12+2/3

1/2.x=3/4

x=3/4:1/2

x=6/4

x=1,5

\(\left(0,75\times64-32\times2\times\frac{3}{4}\right):\left(0,25\times19\times2\times2017\right)\)

= \(\left[64\times\left(0,75-\frac{3}{4}\right)\right]:\left(0,25\times19\times2\times2017\right)\)

= \(\left(64\times0\right):\left(0,25\times19\times2\times2017\right)\)

= \(0:\left(0,25\times19\times2\times2017\right)\)

= \(0\)

 6 x 1/3 + 0,75 + 3/4 : 0,25

=2+0,75+3

=5+0,75

=5,75

\(6.\frac{1}{3}+0,75+\frac{3}{4}:0,25=2+\frac{3}{4}+3=\frac{23}{4}\)

\(6.\frac{1}{3}+0,75+\frac{3}{4}:0,25=\left(6.\frac{1}{3}\right)+0,75+\left(\frac{3}{4}:0,25\right)=2+0,75+3=2,75+3=\frac{23}{4}=5,75\)