Bạn xem lại đề nha \(\dfrac{x+2}{15}\)

\(\dfrac{x+2}{11}+\dfrac{x+2}{12}+\dfrac{x+2}{13}=\dfrac{x+2}{14}+\dfrac{x+2}{15}\)

=> \(\left(x+2\right)\left(\dfrac{1}{11}+\dfrac{1}{12}+\dfrac{1}{13}-\dfrac{1}{14}-\dfrac{1}{15}\right)=0\)

=> x=-2 do  \(\dfrac{1}{11}+\dfrac{1}{12}+\dfrac{1}{13}-\dfrac{1}{14}-\dfrac{1}{15}\)\(\ne0\)

735 = 3 . 5 . 7²

441 = 3² . 7²

294 = 2 . 3 . 7²

ƯCLN(735; 441; 294) = 3 . 7² = 147

\(104-4.\left(x-150\right)=48\)

\(=>4.\left(x-150\right)=104-48\)

\(=>4.\left(x-150\right)=56\)

\(=>x-150=56:4\)

\(=>x-150=14\)

\(=>x=14+150\)

\(=>x=164\)

_________________

\(\left(13x+39\right)-65=26.4^0\)

\(=>\left(13x+39\right)-65=26.1=26\)

\(=>13x+39=26+65\)

\(=>13x+39=91\)

\(=>13x=91-39\)

\(=>13x=52\)

\(=>x=52:13\)

\(=>x=4\)

a) 104.4.(x-150) = 48

4.(x-150) = 104 - 48

4. (x-150) = 56

x-150 = 56 : 4

x-150 = 14

x      = 14 + 150 

x       = 164

(X+3):x

Bạn xem lại đề bài.

\(2^{n+3}-2^{n-2}+2^{n+1}=476\\ \Leftrightarrow8.2^n-\dfrac{2^n}{4}+2.2^n=476\\ \Leftrightarrow\left(8-\dfrac{1}{4}+2\right).2^n=476\\ \Leftrightarrow\dfrac{39}{4}.2^n=476\\ \Leftrightarrow2^n=\dfrac{1904}{39}\)

... Bạn kiểm tra lại đề bài nha

\(A=\left\{x\inℕ;x-2=x+2\right\}\)

Ta thấy \(x-2=x+2\Rightarrow0.x=4\left(vô.lý\right)\)

\(\Rightarrow A=\left\{\varnothing\right\}\)

\(B=\left\{x\inℕ;x:2=x:4\right\}\)

Ta thấy \(x:2=x:4\Rightarrow\dfrac{x}{2}=\dfrac{x}{4}\Rightarrow x.\left(\dfrac{1}{2}-\dfrac{1}{4}\right)=0\Rightarrow x=0\)

\(\Rightarrow B=\left\{0\right\}\)

C = {20; 31; 42; 53; 64; 75; 86; 98}

\(D=A\)a) \(\left\{{}\begin{matrix}A=\left\{x\inℕ^∗|x< 7\right\}\\B=\left\{x\inℕ^∗|3\le x< 8\right\}\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}A=\left\{1;2;3;4;5;6\right\}\\B=\left\{3;4;5;6;7\right\}\end{matrix}\right.\)

b) \(A\cap B=C=\left\{3;4;5;6\right\}\)

c) \(D=B\)\\(A=\left\{7\right\}\)

d) \(D=A\)\\(B=\left\{1;2\right\}\)

Đính chính bỏ \(D=A\) đầu dòng