Tính hợp lí a) -3/8 . 2/5 + -3/8 . 14/5 b) (-17 + |91|) - (91 - |-17| - 2019)
Giải thích
a) −38.25+−38.145=−3.28.5+−3.148.5=−320+−2120=−2420=−65.
b) −17+91−91−−17−2019=−17+91−91−17−2019 =−17+91−91+17+2019 =−17+17+91−91+2019=2019,
a) −38.25+−38.145=−3.28.5+−3.148.5=−320+−2120=−2420=−65.
b) −17+91−91−−17−2019=−17+91−91−17−2019 =−17+91−91+17+2019 =−17+17+91−91+2019=2019,