已知a=2分之1,b=4,求多项式2a的2次方b-3a的2次方b+2a的值

问题描述:

已知a=2分之1,b=4,求多项式2a的2次方b-3a的2次方b+2a
的值

2a^2b-3a^2b+2a
= -a^2b+2a
= -(1/2)^2*4+2*(1/2)
= -1+1
=0

2a的2次方b-3a的2次方b+2a
=-a²b+2a
=-(1/2)²*4+2*(1/2)
=-1+1
=0

2a次方b-3a的2次方b+2a
=-a^2b+2a
=-a(ab-2)
=-1/2*(2-2)
=0