Question

(x +3 ) chia hết cho (x-5)

Answer 1

Answer 2

x+3⋮x-5

⇒(x-5)+8⋮x+3

Vì x-5⋮x-5

⇒8⋮x-5

⇒x-5ϵƯ(8)={1;2;4;8}

⇒xϵ{6;7;9;13}

Vậy xϵ{6;7;9;13}

Answer 3

(x +3 ) ⋮ (x-5)

=> (x+3)-(x-5) ⋮(x-5)

=> (x+3-x+5)⋮(x-5)

=> 8⋮(x-5)

=> x-5∈Ư(8)=\(\left\{\pm1;\pm2;\pm4;\pm8\right\}\)

ta có bảng sau:

x-5	-8	-4	-2	-1	1	2	4	8
x	-3	1	3	4	6	7	9	13

vậy x∈{-3;1;3;4;6;7;9;13}