若代数式2a²-3b+6=4,求下列代数式的值:(1)4a²-6a+1;?(2)-a²+3

2a²-3b+6=4
2a²-3b=-2
4a²-6b+1
=2(2a²-3b)+1
=-2x2+1
=-4+1
=-3
-a²+3/2a-1
=-1/2(2a²-3b)-1
=1/2x2-1
=1-1
=0