计算 m^2+4m-3m^2-5m+6m^2-2,其中m=-3/2 5ab-7a^2b^2-8ab+5a^2b^2-ab,其中a=_数学解答

计算 m^2+4m-3m^2-5m+6m^2-2,其中m=-3/2 5ab-7a^2b^2-8ab+5a^2b^2-ab,其中a=1/2,b=-2

人气：194 ℃　时间：2020-03-30 20:54:13

解答

解
m²+4m-3m²-5m+6m²-2
=(m²-3m²+6m²)+(4m-5m)-2
=4m²-m-2
=4×(-3/2)²-(-3/2)-2
=9+3/2-2
=7+3/2
=17/2
5ab-7a²b²-8ab+5a²b²-ab
=(5ab-8ab-ab)+(5a²b²-7a²b²)
=-4ab-2a²b²
=-4×1/2×(-2)-2×(1/2)²(-2)²
=4-2
=2