56 000 : \(x\)    = 8

              \(x\)    = 56 000 : 8

              \(x\)     = 7 000

x * 9 + x = 5600

x * 9 + x * 1 = 5600

x * ( 9 + 1 ) = 5600

x * 10 = 5600

x = 5600 : 10

x = 560

X=560      

               560

\(\frac{x}{4}=\frac{y}{8}\Rightarrow\frac{x^2}{16}=\frac{y^2}{64}=\frac{xy}{32}=\frac{5600}{32}=175\left(1\right)\)

(=> tìm x,y

Ta có: x/4 = y/8 = x.y/ 4.8 = 5600/32 = 175 (1)

Từ (1) => x = 700 ; y = 1400

k nha

Cách 1: \(5x^2-60x-5600=0\)\(\Leftrightarrow x^2-12x-1120=0\)\(\Leftrightarrow x^2-40x+28x-1120=0\)

\(\Leftrightarrow x\left(x-40\right)+28\left(x-40\right)=0\)\(\Leftrightarrow\left(x-40\right)\left(x+28\right)=0\)\(\Leftrightarrow\orbr{\begin{cases}x-40=0\\x+28=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=40\\x=-28\end{cases}}\)

Vậy \(\orbr{\begin{cases}x=40\\x=-28\end{cases}}\)

Cách 2: \(5x^2-60x-5600=0\)\(\Leftrightarrow x^2-12x-1120=0\)\(\Leftrightarrow x^2-2x.6+6^2-1156=0\)

\(\Leftrightarrow\left(x-6\right)^2-34^2=0\)\(\Leftrightarrow\left(x-6-34\right)\left(x-6+34\right)=0\)

\(\Leftrightarrow\left(x-40\right)\left(x+28\right)=0\)\(\Leftrightarrow\orbr{\begin{cases}x-40=0\\x+28=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=40\\x=-28\end{cases}}\)

Vậy \(\orbr{\begin{cases}x=40\\x=-28\end{cases}}\)

\(37\times x+53\times x+x\times10=5600\)

\(x\times\left(37+53+10\right)=5600\)

\(x\times100=5600\)

\(x=5600\div100\)

\(x=56\)

\(x\) x ( 37 + 53 +10 ) = 5600

\(x\) x 100 = 5600

\(x\) = 5600 : 100

\(x\) = 56

Tick cho mình

\(1000^x+120+1000^x=\)\(5600\)

\(\Rightarrow2.1000^x=5600-120\)

\(\Rightarrow2.1000^x=5480\)

\(\Rightarrow1000^x=2740\)

-Vậy phép tính này vô lý 

P/s :

-Ko chắc ...

-Hok tốt a~

a)\(x.99+x=100\)

\(\Rightarrow x.\left(99+1\right)=100\)

\(\Rightarrow x.100=100\)

\(\Rightarrow x=1\)

b)\(420+65.x=\left(x+175\right):5+30\)

\(420+65.x=\left(x+175\right).\dfrac{1}{5}+30\)

\(420+65.x=\dfrac{1}{5}x+35+30=\dfrac{1}{5}x+65\)

\(\Rightarrow420-65=\dfrac{1}{5}x-65x\)

\(\Rightarrow-64,8x=355\)

\(\Rightarrow x=-\dfrac{1775}{324}\)

c)\(x:\left[\left(1800+600\right):30\right]=5600:\left(315-35\right)\)

\(x:80=20\Rightarrow x=20.80=1600\)