Question

Bài 1 : Tính nhanh

a) (135-35) . (-37)+37.(-42-58)

b) -65.(87-17)-87.(17-65)

c) [3.(-2)-(-8)] .(-7)-(-2).(-5)

Answer 1

a, (135-35).(-37)+37.(-42-58)

= 100.(-37)+37.(-100)

= 100.(-37)+(-37).100

= (-37).(100+100)

= (-37).200

= -7400

Answer 2

b, -65.(87-17)-87.(17-65)

= -65.70-87.(-48)

= -4550+4176

=-374

Answer 3

c, [3.(-2)-(-8)].(-7)-(-2).(-5)

= [(-6)+8].(-7)+(-10)

= 2.(-17)

= -34