16,24 x X + X x 23,76 = 2,8

( 16,24 + 23,76 ) x X = 2,8

40 x X = 2,8

X = 2,8 : 40

X = 0,07

X ( 16,24+ 23,76) = 2,8

=> X x 40 = 2,8

=> X= 0,07

Vậy X= 0,07

\(16,24\times x+x\times23,76=2,8\)

\(x\times\left(16,24+23,76\right)=2,8\)

\(x\times40=2,8\)

\(\Rightarrow x=2,8:40=\frac{7}{100}\)

Vậy ...

=> X x (16,24+23,76)=2,8

X x 40 = 2,8

X = 2,8 : 40

X = 0,07

16.24 x X + X x 23.76 = 2.8

X x ( 16.24 + 23.76 )  = 2.8

X x 40                       = 2.8

X                              = 2.8 : 40

X                              = 0.07

->x x(16,24+23,76)=2,8

    16,24.x+x.23,76=2,8

=>x.(16,24+23,76) =2,8

=>x.40                  =2,8

=>x                       =2,8:40

=>x                       =0,07

 Vậy x = 0,07

|x+y-2,8|>0 ;|y+z+4|>0;|z+x-1/4|>0

mà theo đề :|x+y-2,8|+|y+z+4|+|z+x-1/4|=0

=>|x+y-2,8|=|y+z+4|=|z+x-1/4|=0

+)x+y-2,8=0=>x+y=2,8   (1)

+)y+z+4=0=>y+z=-4    (2)

+)z+x-1/4=0=>z+x=1/4   (3)

cộng từng vế 3 đẳng thức của 1,2,3 ta có:

x+y+y+z+z+x=2x+2y+2z=-0,95

=>2(x+y+z)=-0,95

=>x+y+z=-0,475

lại có x+y=2,8=> z=...

y+z=..=>...

z+x=...=>....

2,3:2,8*x=57,5

=>x=70

0,16:(x:3,5)=2,8

=>x=0,2

a, \(=16,24\left(12-3+1\right)\)

\(=16,24.10=162,4\)

b, \(=1,25\left(1+2+7\right)\)

\(=1,25.10=12,5\)

c, \(=2,46\left(2+8\right)\)

\(=2,46.10=24,6\)

\(a,=16,24\times12-16,24\times3+16,24\times1\\ =16,24\times\left(12-3+1\right)=16,24\times10=162,4\\ b,=1,25\times\left(1+2+7\right)=1,25\times10=12,5\)

a 16.24( 12-10+3)=16.24 x 5=81.2

b  1.25(1+2+7)=1.25 x 10= 12.5

c  2.46 x 2 + 2.46 x8 = 2.46(2 + 8)=2.46 x 10=24.6

Xx3,6=0,17x0,9

Xx3,6=0,153

X=0,153÷3,6

X=0,0425

2,3:2,8xX=57,5

2,8×X=2,3:57,5

2,8×X=0,04

X=0,04:2,8

X=0,01428571429

0,16:(x:3,5)=2,8

X:3,5=0,16:2,8

X:3,5=0,05714285714

X=0,05714285714×3,5

X=0.2

x*3,6=0,17*0,9

x*3,6=0,153

x=0,153:3,6

x=0,0425