Question

tìm x

30-5x chia hết cho x

x+20 chia hết cho x+1

2x+10 chia hết cho 2x+1

giúp mik nha, cảm ơn nhiều

(giúp mik mik tick cho)

Answer 1

\(30-5x⋮x\)

\(\Leftrightarrow30-5x+5x⋮x\left(\text{vì: 5x chia hết cho x}\right)\)

\(\Rightarrow30⋮x\Rightarrow x\in\left\{-1;1;-2;2;-3;3;-5;5;-6;6;-10;10;-15;15;-30;30\right\}\)

Answer 2

\(x+20⋮x+1\Leftrightarrow\)

\(\left(x+20\right)-\left(x+1\right)⋮x+1\Leftrightarrow19⋮x+1\)

\(\Leftrightarrow x+1\in\left\{-1;1;-19;19\right\}\Leftrightarrow x\in\left\{-2;0;-20;18\right\}\)

Answer 3

thank shitboXD

Answer 4

\(2x+10⋮2x+1\)

\(\Leftrightarrow\left(2x+10\right)-\left(2x+1\right)⋮2x+1\)

\(\Leftrightarrow9⋮2x+1\Leftrightarrow2x+1\in\left\{-1;1;-3;3;-9;9\right\}\)

\(\Leftrightarrow x\in\left\{-1;0;-2;1;-5;4\right\}\)

Ko có J đâu tớ rảnh nên tớ giúp :)