Bài 1. Tính hợp lý

1) (–12) +6.(–3)

2) (36 -2020) + (2019 -136) – 27

3) (144 – 97) – (244 – 197)

4) (–24).13 – 24.( –3)

5) 54+55+56+57+58-(64+65+66+67+68)

6) 24(16 – 5) – 16(24 – 5)

7) 47.(23 + 50) – 23.(47 + 50)

8) (-31). 47 + (-31). 52 + (-31)

Bài 2: Tìm số nguyên x, biết:

1)-17-(2x-5)=-6

2) 10-2(4-3x)=-4

3)-12+3(-x+7)=-18

4)-45:[5.(-3-2x)]=3

5) x.(x+3)=0

6) (x-2).(x+4)=0

7) x.(x+1).(x-3)=0