Question

tính hợp lí

a)32-4*(8-7)

b)5*(12-3)-12*(5-3)

 

Answer 1

a)32-4.(8-7)

= 32 - 4.1

= 32 - 4

= 28

b)5.(12-3)-12.(5-3)

= 5.9 - 12.2

= 45 - 24

= 21

Answer 2

a) 32 - 4(8 - 7)

= 32 - 4.1

= 32 - 4

= 28

b) 5(12 - 3) - 12(5 - 3)

= 5.12 - 5.3 - (12.5 - 12.3)

= 5.12 - 5.3 - 12.5 + 12.3

= (5.12 - 12.5) - (5.3 - 12.3)

= 0 - 3(5 - 12)

= 0 - 3.(-7)

= 0 - (-21)

= 21