\(\overline{x3}+\overline{3x}=12\times11\)

\(x\times10+3+30+x=12\times11\)

\(x\times10+3+30+x=132\)

\(x\times11 +33=132\)

\(x\times11=132-33\)

\(x\times11=99\)

\(x=99:11\)

\(x=9\)

(P/S : Đây là lần đầu chị làm bài này , nếu sai thì cho chj xin lỗi)

x3 là cái j đó em?

\(58-7=51\)

\(26-4=22\)

\(38+7=45\)

\(22+6=28\)

\(99-8=91\)

\(87-5=82\)

\(68+9=77\)

\(44+53=97\)

$\color{#976D00}{\text{@}}$$\color{#C18C00}{\text{A}}$$\color{#D59B00}{\text{n}}$$\color{#F3C246}{\text{n}}$

Đề thiếu rồi!

Ta có :

\(A.5,78\times10=57,8\)

\(B.57,8\times0,1=57,8:10=5,78\)

\(C.57,8\times0,01=57,8:100=0,578\)

\(D.5,78\times0,001=5,78:1000=0,00578\)

Vì \(0,00578< 0,578< 5,78< 57,8\) nên

\(=>D< C< B< A=>D\) bé nhất.

\(=>\) Chọn \(D\)

$\color{#976D00}{\text{@}}$$\color{#C18C00}{\text{A}}$$\color{#D59B00}{\text{n}}$$\color{#F3C246}{\text{n}}$

\(0,5+3\dfrac{1}{2}-4\)

\(=\dfrac{1}{2}+\dfrac{7}{2}-\dfrac{8}{2}\)

\(=\dfrac{1+7-8}{2}\)

\(=0\)

$\color{#87CEFA}{\text{@456(An)}}$

\(x+x+x+x\times97=12300\)

\(x\times1+x\times1+x\times1+x\times97=12300\)

\(x\times\left(1+1+1+97\right)=12300\)

\(x\times100=12300\)

\(x=12300:100\)

\(x=123\)

Cho mik sửa lại:

\(x+x+x+x\times4=2400\)

\(x\times1+x\times1+x\times1+x\times4=2400\)

\(x\times\left(1+1+1+4\right)=2400\)

\(x\times7=2400\)

\(x=2400:7\)

\(x=\dfrac{2400}{7}\)

\(x+x+x+x\times4=2400\)

\(4x\times4=2400\)

\(4x=2400:4\)

\(4x=600\)

  \(x=600:4\)

  \(x=150\)

\(x+x+x+...+x=1251\)

\(9x=1251\)

  \(x=1251:9\)

  \(x=139\)

(Nếu sai thì cho mik xin lỗi)