bài 1
a) (–5). (–4) + 12: (–4) – 1
=20-3-1
=16
b) 12 - 2. (–3) + (–7)
=12+6-7
=11
bài 2
a) x: (–6) + 16 = 10
x:(-6)=10-16
x:(-6)=-6
x=1
b) (7 – x). 12 – (–12): 6 = –10
84-12x+2=-10
12x=84+10-2
12x=92
x=$\dfrac{23}{3}$
Bài 3:
a) – (125 – 241) + (–241 – 175) – (–200)
=-125+241-241-175+200
=(-125-175+200)+(241-241)
=-100
b) (–287 + 269) – (–131 + 113) – (–300)
=–287 + 269 +131 - 113+300
=(–287-113+300) + (269 +131)
=-100+400
=300