Question

Tìm x thuộc Z:
1. x.(x+7) = 0
2 . (x+12).(x-3)= 0
3. (-x+5).(3-x)=0
4. x.(2+x).(7-x)=0
5. (x-1).(x+2).(-x-3)=0
Giải được 3/5 mình sẽ tick nhưng mong các bạn giải hết cho mình.

Answer 1

bài 1: x.(x+7) = 0

Th1:x=0              Th2:x+7=0

                          =>x=-7

bài 2 (x+12).(x-3)= 0

Th1:x+12=0                                         Th2:x-3=0

=>x=-12                                                =>x=3

bài 3 (-x+5).(3-x)=0

Th1 (-x)+5=0                                          Th2:3-x=0

=>-x=-5                                                  =>x=3

bài 4 x.(2+x).(7-x)=0

Th1:x=0                                               Th3:7-x=0

Th2:2+x=0                                             =>x=7

=>x=-2

bài 5 (x-1).(x+2).(-x-3)=0

Th1:x-1=0                                               Th2:x+2=0

=>x=1                                                   =>x=-2

Th3:-x-3=0

=>-x=-3