Question

tínhnhanh

2018x2018-2017x2019

Answer 1

\(2018\cdot2018-2017\cdot2019\)

\(=2018\cdot2018-2017\left(2018-1\right)\)

\(=2018\cdot2018-2017\cdot2018-2017\cdot1\)

\(=2018\left(2018-2017\right)-2017\cdot1\)

\(=2018\cdot1-2017\cdot1\)

\(=1\)

Answer 2

\(2018\cdot2018-2017\cdot2019\)

\(=(2019-2018)\cdot(2018-2017)\)

\(=1\)

Answer 3

\(2018\times2018-\left(2018-1\right)\times\left(2018+1\right)=2018\times2018-2018\times2018-2018+2018-1\)

\(=-1\)