Question

TÌM STN x BIẾT :

a) 6chia hết cho (x-1)

b) 15 chia hết cho (2x+1)

Answer 1

a) 6 chia hết cho (x-1) => x-1 = 6 x = 6+1 Vậy: x = 7 b)15 chia hết cho (2.x+1) => (2.x+1)=15 2.x =15-1 2.x =14 x =14:2 Vậy: x =7

Answer 2

giúp mình nhé ai làm được thi kb nhé

Answer 3

a) \(6⋮\left(x-1\right)\)

\(\Rightarrow\left(x-1\right)\inƯ\left(6\right)\)

\(Ư\left(6\right)=\left\{1;2;3;6\right\}\)

Có: \(\left(x-1\right)\inƯ\left(6\right)\)

\(\Rightarrow\left(x-1\right)\in\left\{1;2;3;6\right\}\)

\(\Rightarrow x-1=1;x-1=2;x-1=3;x-1=6\)

\(\Leftrightarrow x=2;x=3;x=4;x=7\)

\(\Rightarrow x\in\left\{2;3;4;7\right\}\)

b) \(15⋮\left(2x+1\right)\)

\(\Rightarrow\left(2x+1\right)\inƯ\left(15\right)\)

\(Ư\left(15\right)=\left\{1;3;5;15\right\}\)

Có: \(\left(2x+1\right)\inƯ\left(15\right)\)

\(\Rightarrow\left(2x+1\right)\in\left\{1;3;5;15\right\}\)

\(\Rightarrow2x+1=1;2x+1=3;2x+1=5;2x+1=15\)

\(\Leftrightarrow x\in\varnothing;x=1;x=2;x=7\)

\(\Rightarrow x\in\left\{1;2;7\right\}\)

Answer 4

nha bac tuan co 3 dan vit chan tha tren cac canh dong khac nhau. So vit trg cac dan la 132 con;con va 306 con.Bac Tuan noi neu dem tat ca so vit do nhot deu vao 3 chuong hoac 9 chuong ko thua con nao.