giải chi tiết giúp mik ạ

a: =11-11=0

c: =23x100=2300

\(y\times28+y\times73-y=3200\\\Rightarrow y\times\left(28+73-1\right)=3200\\ \Rightarrow y\times100=3200\\ \Rightarrow y=3200:100\\ \Rightarrow y=32\)

a) \(\text{ y.28 + y.73 - y = 3200}\)

⇒ \(y.\left(28+73-1\right)=3200\)

⇒ \(y.100=3200\)

⇒ \(y=32\)

Dấu chấm là dấu nhân

y x 28 + y x 73 - y = 3200
y (28 + 73 - 1) = 3200
y x 100 = 3200
y = 3200 : 100
y = 32

\(\frac{4}{x}\) \(=\frac{1}{5}\)

Ta có :

\(\frac{4}{x}\) \(=\frac{4}{20}\)

=> \(x=20\)

#Ninh Nguyễn

x.1=4.5

x.1=20

x=20:1

x=20

x.1 = 4.5

x.1 = 20

x    = 20

Vậy x = 20

a: =>5x-30=25

hay x=11

\(a,x=\dfrac{1}{2};y=-100\)

\(\Rightarrow A=\dfrac{1}{2}\left[\left(\dfrac{1}{2}\right)^2+100\right]-\left(\dfrac{1}{2}\right)^2\left(\dfrac{1}{2}-100\right)-100\left[\left(\dfrac{1}{2}\right)^2-\dfrac{1}{2}\right]\)

\(\Rightarrow A=100\)

\(b,x=-1\)

\(\Rightarrow B=\left[\left(-1\right)^2-5\right]\left(-1+3\right)+\left(-1+4\right)\left[-1-\left(-1\right)^2\right]\)

\(\Rightarrow B=-14\)

\(c,x=-2\)

\(\Rightarrow C=-6\left(5.4-2\right)-5.4\left(7-6\right)-2,5\left(2-14.4\right)\)

\(\Rightarrow C=7\)

\(d,\left|x\right|=2\)

\(TH_1:x\ge0\)

\(D=\left(3.2+5\right)\left(2.2-1\right)+\left(4.2-1\right)\left(3.2+2\right)=89\)

\(TH_2:x< 0\)

\(D=\left(-6+5\right)\left(-4-1\right)+\left(-8-1\right)\left(-6+2\right)=41\)

B nhé

`9,`

`a, 5/6+1/6 \div 4/3`

`= 5/6+1/8`

`= 23/24`

`b,`

`15/4*(-2/3+3/4)+15/4*(-1/3+1/4)`

`= 15/4*[(-2/3+3/4)+(-1/3+1/4)]`

`= 15/4*[(-2/3)+3/4-1/3+1/4]`

`= 15/4*[(-2/3-1/3)+(3/4+1/4)]`

`= 15/4*(-1+1)`

`= 15/4*0=0`

`10,`

`a, 35 - 3(x-30)=20`

`35- 3x-90=20`

`35+90-3x=20`

`125-3x=20`

`3x=125-20`

`3x=105`

`x=105 \div 3`

`x=35`

`b,`

`|2x-1/2|=3/2`

`=>`\(\left[{}\begin{matrix}2x-\dfrac{1}{2}=\dfrac{3}{2}\\2x-\dfrac{1}{2}=-\dfrac{3}{2}\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}2x=\dfrac{3}{2}+\dfrac{1}{2}\\2x=-\dfrac{3}{2}+\dfrac{1}{2}\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}2x=2\\2x=-1\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}x=1\\x=-\dfrac{1}{2}\end{matrix}\right.\)

+Gọi a là số cần tìm . 

Nếu a + 1 thì a chia hết cho 4 . 

0 : 4 = 0 

nên chia cho 4 dư 3 thì 0 + 3 = 3 

đáp số : 3 

k mình nha