( 4.578 : 3.27 + 0.872 : 2.18 ) x 6.04 - 3.245 

= ( 1.4 + 0.4 ) x 6.04 - 3.245 

= 1.8 x 6.04 - 3.245

= 10.872 - 3.245

= 7.627

500 × 4 × 2 × 25 - 500 × 3 × 2 × 30

= 500 × (4 × 2 × 25) - 500 × (3 × 2 × 30)

= 500 × 200 - 500 × 180

= 500 × (200 - 180)

= 500 × 20

= 10000

\(5x+40:2=45\)

\(5x+20=45\)

\(5x=45-20\)

\(5x=25\)

\(x=25:5\)

\(x=5\)

_______

\(x+30=40-2.5^2\)

\(x+30=40-2.25\)

\(x+30=40-50=-10\)

\(x=\left(-10\right)-30\)

\(x=-40\)

bạn tui làm đúng ghê!!!

@Phương

a) x(x+1)=2+4+6+8+...+2500

x(x+1)=(2500+2).1250:2

x(x+1)=1563750

Ta thấy: x và x+1 là 2 số liên tiếp

Mà x(x+1)=1563750=>x=1250;x+1=1251

Vậy x=1250

b) x-3=12:{390:[500-(5^3+7^2.5)]}

x-3=12:[390:(500-254.64)]

x-3=12:(390:245.35)

x-3=12:1.58

x-3=7.54

=>x=10.5

Vậy x=10.5

c) x+3^3.12=3^3.19

=>x=2.46

Vậy x=2.46

60×20×30×40+500

120×30×40+500

3600×40+500

144000+500

144500

Trả lời 

\(20\times30\times20\times30\times40+500\)

\(=600\times600\times40+500\)

\(=360000\times40+500\)

\(=14400000+500\)

\(=14400500\)

14400500

\(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+...+\left(x+30\right)=500\)

Số lượng số hạng là: \(30-1+1=30\)

\(\Rightarrow30x+\dfrac{30\left(30+1\right)}{2}=500\)

\(30x+465=500\)

\(30x=35\)

\(x=\dfrac{7}{6}\)

\(\left(x+1\right)+\left(x+2\right)+...+\left(x+30\right)=500\)

\(\Rightarrow x+1+x+2+..+x+30=500\)

\(\Rightarrow\left(x+x+...+x\right)+\left(1+2+...+30\right)=500\)

\(\Rightarrow30\cdot x+465=500\)

\(\Rightarrow30\cdot x=500-465\)

\(\Rightarrow30\cdot x=35\)

\(\Rightarrow x=\dfrac{35}{30}\)

\(\Rightarrow x=\dfrac{7}{6}\)

GIÚP MÌNH VỚI Ạ 

\(27x+30x+43x=210500\)

\(100x=210500\)

\(x=210500:100\)

\(x=2105\)

vậy \(x=2105\)

= a x (27 + 30 + 43 )

= a x 100

= 210 500 : 100

= a = 2105

X x 27 + X x 30 + X x 43 = 210 500 . 

X x 100                            = 210 500 . 

X                                      = 210 500 : 100 . 

X                                      = 2105 . 

\(BCNN\left(12;25;30\right)=300\)

\(\Rightarrow x=300\) ( t/m điều kiện )

`=> x in BC(12, 25, 30)`.

Ta có: `12 = 2^2 xx 3`.

`25 = 5^2`.

`30 = 5 xx 2 xx 3`.

`=> x in B(300)`.

`=> x in {0, 300, 600, ...}` mà `0 <= x <= 500`

`=> x = 0, 300`.

`=>` Ta có:

`BCNNN (12; 25; 30) = 300`

`=>` `x = 300` vì:

`0 <= x <= 500`