8,75 * x + 1,25 * x = 20

8,75 * x + 1,25 * x = 20

x                          = 20 : ( 8,75 + 1,25 )

x                          = 20 : 10

x                          = 2

\(8,75\times x+1,25\times x=2\)
\(\left(8,75+1,25\right)\times x=2\)
\(10\times x=2\)
\(x=2:10\)
\(x=0,2\)

8,75 x X +1,25 x X = 280

X x [ 8,75 + 1,25 ] = 280

X x 10 = 280

X         =  280 / 10

X        = 28

giúp với đang gấp nha

sai rồi nguyen le bao nuyen tớ bấm nhầm thích đấy sai rồi 

sai từ cái đầu bai của cậu đấy

=8.75+1.25)xX=2

10xX=2

X=2:10

X=0.2

đún thì cho mk nhé

chúc bạn học tốt

8,75 x X + 1,25 x X = 2

X x ( 8,75 + 1,25 ) = 2

X x 10 = 2

X = 2 : 10

X = 0,2

\(8,75.x+1,25.x=2\)

\(< =>x\left(8,75+1,25\right)=2\)

\(< =>x.10=2\)

\(< =>x=2:10=\frac{2}{10}=\frac{1}{5}\)

\(25.5.4.125.20.8\)

\(=\left(25.4\right).\left(5.20\right).\left(125.8\right)\)

\(=100.100.1000\)

\(=10000000\)

25*(5+5)*4*20*8

=250*20+4+8

= 5000*12

=60000

đúng mk tích cho .

`#040911`

`a,`

`15 + 25 \div (2x - 1) = 20`

`\Rightarrow 25 \div (2x - 1) = 20 - 15`

`\Rightarrow 25 \div (2x - 1) = 5`

`\Rightarrow 2x - 1 = 25 \div 5`

`\Rightarrow 2x - 1 = 5`

`\Rightarrow 2x = 6`

`\Rightarrow x = 3`

Vây, `x = 3.`

`b,`

\(3^{x-1}+2\cdot3^x=21\)

`\Rightarrow 3^x \div 3 + 2. 3^x = 21`

`\Rightarrow 3^x . \frac{1}{3} + 2. 3^x = 21`

`\Rightarrow 3^x . (\frac{1}{3} + 2) = 21`

`\Rightarrow 3^x . \frac{7}{3} = 21`

`\Rightarrow 3^x = 21 \div \frac{7}{3}`

`\Rightarrow 3^x = 9`

`\Rightarrow 3^x = 3^2`

`\Rightarrow x = 2`

Vậy, `x = 2.`

`c,`

\(2^{x-3}+2^{x+1}=17\)

`\Rightarrow 2^x \div 2^3 + 2^x . 2 = 17`

`\Rightarrow 2^x . \frac{1}{8} + 2^x . 2 = 17`

`\Rightarrow 2^x . (\frac{1}{8} + 2) = 17`

`\Rightarrow 2^x . \frac{17}{8} = 17`

`\Rightarrow 2^x = 17 \div \frac{17}{8}`

`\Rightarrow 2^x = 8`

`\Rightarrow 2^x = 2^3`

`\Rightarrow x = 3`

Vậy, `x = 3`

`d,`

\(5^x-5^{x-1}=20\)

`\Rightarrow 5^x - 5^x \div 5 = 20`

`\Rightarrow 5^x - 5^x . \frac{1}{5} = 20`

`\Rightarrow 5^x . (1 - \frac{1}{5} = 20`

`\Rightarrow 5^x . \frac{4}{5} = 20`

`\Rightarrow 5^x = 20 \div \frac{4}{5}`

`\Rightarrow 5^x = 25`

`\Rightarrow 5^x = 5^2`

`\Rightarrow x = 2`

Vậy, `x = 2.`

\(a.25:\left(2x-1\right)=5\)

\(2x-1=5\Leftrightarrow2x=6\Leftrightarrow x=3\)

\(b.3^x:3+2.3^x=21\)\(\Leftrightarrow3^x.\dfrac{1}{3}+2.3^x=21\)

\(\Leftrightarrow3^x\left(\dfrac{1}{3}+2\right)=21\)

\(\Leftrightarrow3^x.\dfrac{7}{3}=21\)

\(\Leftrightarrow3^x=9\Leftrightarrow x=2\)

\(c.2^x:2^3+2^x.2=17\Leftrightarrow2^x.\dfrac{1}{8}+2^x.2=17\)

\(\Leftrightarrow2^x.\dfrac{17}{8}=17\Leftrightarrow2^x=8\Leftrightarrow x=3\)

\(d.5^x-5^x:5=20\Leftrightarrow5^x-5^x.\dfrac{1}{5}=20\)

\(\Leftrightarrow5^x\left(1-\dfrac{1}{5}\right)=20\Leftrightarrow5^x=20:\dfrac{4}{5}\Leftrightarrow5^x=25\Leftrightarrow x=2\)

Ai biết chỉ mình nha 

1. 11(x-9)=77

x-9=7

x=16

2. 4(x-3)=48

x-3=12

x=15

3.3(x-8)=81

(x-8)=27

x=35

\(40-21:\left(2.x+3\right)=33\)

\(21:\left(2.x+3\right)=40-33\)

\(21:\left(2.x+3\right)=7\)

\(\left(2.x+3\right)=21:7\)

\(\left(2.x+3\right)=3\)

\(2.x=3-3\)

\(2.x=0\)

\(x=0:2\)

\(x=0\)

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

X x ( 8,75 + 1,25 ) = 20 

X x 10 = 20 

X = 2

( 8,75 + 1,25 ) x X = 20

         10 x X = 20

                X = 20 : 10

                X = 2

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

X x (8,25 + 1,25)     = 20

X x 10                      = 20

X                              = 20 : 10

X                              =2

Vậy X = 2

~~~HOK TỐT NHA~~~

a: \(=\dfrac{5}{4}\cdot\dfrac{2}{5}\cdot\dfrac{17}{21}\cdot\dfrac{7}{34}=\dfrac{1}{2}\cdot\dfrac{1}{2}\cdot\dfrac{1}{3}=\dfrac{1}{12}\)

b: =>0,5^x(0,5+1)=1,5

=>0,5^x=1

=>x=0

c: =>x*0,05-0,25*x=-1,2

=>-0,3*x=-1,2

=>x=4

d: =>x-1=1 hoặc x-1=-1

=>x=0 hoặc x=2

e: =5+4=9