(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

\(0⋮3\) nhé.

chia hết vì 0 chia hết cho mọi số khác 0

( \(0⋮ℕ^∗\) )

\(60=2^2\cdot3\cdot5\)

\(280=2^3\cdot5\cdot7\)

Các thừa số chung lớn nhất \(2^3\cdot5\)

BCNN=\(2^3\cdot5\cdot3\cdot7=840\)

\(60=2^2.3.5\)

\(280=2^3.3.5\)

\(\Rightarrow BCNN\left(60;280\right)=2^3.3.5=280\)

a) \(A=\left\{4\right\}\)

\(A=\left\{x|x\inℕ;3< x< 5\right\}\)

b) \(B=\left\{10;11\right\}\)

\(B=\left\{x|x\inℕ;10\le x\le11\right\}\)

c) \(C=\left\{0;1;2;3;4;5\right\}\)

\(C=\left\{x|x\inℕ;x\le5\right\}\)

d) \(D=\left\{10;12;14;16\right\}\)

\(A=\left\{x|x\inℕ;x=2k;5\le k\le8;k\inℕ\right\}\)

e) \(E=\left\{1;3;5;7;9;11;13\right\}\)

\(A=\left\{x|x\inℕ;x=2k-1;1\le k< 8;k\inℕ\right\}\)

f) \(F=\left\{4;8;12;16\right\}\)

\(A=\left\{x|x\inℕ;x=4k;1\le k\le4;k\inℕ\right\}\)