Question

a) 70 - 5. (x - 3 ) = 3² . 5

b) 10 chia hết ( x -3 )

Answer 1

a) x = 8

b) x = 4; 5; 8; 13

Answer 2

70 - 5 . (x-3) = 3².5

<=>70- 5.(x-3)=45

<=>5.(x-3)=70-45

<=>5.(x-3)=35

<=>x-3=35:5

<=>x-3=7

<=>x=7+3

<=>x=10

b) 10 chia hết cho x-3

=>x-3 thuộc U(10)={1;-1;2;-2;5;-5;10;-10}

=>x thuộc {4;2;5;1;8;-2;13;-7}