-1911(1234-1911)
= -1911. (- 677)
= 1293747
-1911( 1234 - 1911)
= -1911 . (-677)
=1293747
Cách 1: \(-1911\left(1234-1911\right)\\ =-1911\cdot\left(-677\right)\\ =1293747\)
Cách 2: \(-1911\left(1234-1911\right)\\ =-1911\cdot1234-\left(-1911\right)\cdot1911\\ =-2358174-\left(-3651921\right)\\ =-2358174+3651921\\ =1293747\)