Question

Tìm x\(\in\)Z biết:

a)2.(x-3)-3.(x-5)=4.(3-x)-18

b)-2x-11 chia hết cho 3x+2

Answer 1

a)

2.(x-3)-3.(x-5)=4.(3-x)-18

<=>2x-6-3x+15 =12-4x-18

<=>9-x =-4x-6

<=>9-x+4x+6 =0

<=>3x+15 =0

<=>3x =-15

<=>x =-5

Answer 2

a: =>2x-6-3x+10=12-4x-18

=>-x+4=-4x-6

=>3x=-10

=>x=-10/3

b: =>6x+33 chia hết cho 3x+2

=>6x+4+29 chia hết cho 3x+2

=>\(3x+2\in\left\{1;-1;29;-29\right\}\)

=>\(x\in\left\{-\dfrac{1}{3};-1;9;-\dfrac{31}{3}\right\}\)