Ta có: 0,1:x+0,2:x+0,3:x+0,4:x+0,5:x=0,5

=>(0,1+0,2+0,3+0,4+0,5):x=0,5

=>1,5:x=0,5

=>x=1,5:0,5=3

a)(-2,5 x 0,38 x 0,4) - [0,125 x 3,15 x (-8)]

=[(-2,5 x 0,4) x 0,38] - [(-8 x 0,125) x 3,15]

=(-1 x 0,38) - (-1 x 3,15)

=(-0,38) - (-3,15)

=2,77

a) 2,77

b)-2

`x:0,5+x:0,2-x=6,3`

`=> x xx 2 + x xx 5 - x =6,3`

`=> x xx (2+5-1)=6,3`

`=> x xx 6 = 6,3`

`=> x=6,3:6`

`=> x=1,05`

cc

`@` `\text {Ans}`

`\downarrow`

`x \div 0,2 + x \div 0,5 - x \times 2 = 12,03`

`x \div 2/10 + x \div 5/10 - x \times 2 = 12,03`

`x \times 10/2 + x \times 10/5 - x \times 2 = 12,03`

`x \times 5 + x \times 2 - x \times 2 = 12,03`

`x \times ( 5+2-2) = 12,03`

`x \times 5 = 12,03`

`x = 12,03 \div 5`

`x =2,406`

Vậy, `x = 2,406.`

\(x\times\dfrac{1}{5}+x\times\dfrac{1}{2}+x\times\dfrac{1}{4}-x=45,5\)

\(x\times\left(\dfrac{1}{5}+\dfrac{1}{2}+\dfrac{1}{4}-1\right)=45,5\)

\(x\times-0,05=45,5\)

\(x=-910\)

X : 0,2 + X : 0,5 = 4,27

X : ( 0,2 + 0,5)   = 4,27

X : 0,7                = 4,27

X                         = 4,27 x 0,7

X                         = 2,989

=>5x+4x+2x=1,32

=>11x=1,32

=>x=0,12

a: \(24,8:0,5+24,8\cdot3+24,8:0,2\)

\(=24,8\cdot2+24,8\cdot3+24,8\cdot5\)

\(=24,8\left(2+3+5\right)\)

\(=24,8\cdot10=248\)

b: \(19,5+19,5\cdot3+19,5:0,5+19,5:0,25\)

\(=19,5+19,5\cdot3+19,5\cdot2+19,5\cdot4\)

\(=19,5\left(1+3+2+4\right)\)

\(=19,5\cdot10=195\)

c: \(121,07\cdot4+121,07:0,25+121,07:0,5\)

\(=121,07\cdot4+121,07\cdot4+121,07\cdot2\)

\(=121,07\left(4+4+2\right)\)

\(=121,07\cdot10=1210,7\)