化简:⑴(x²-y²) -4 (2x²-3y)

问题描述:

化简:⑴(x²-y²) -4 (2x²-3y)
⑵4x-3﹙1-3/2x﹚+4﹙2-x/4﹚
⑶3﹙a²-2ab﹚-2﹙-3ab+b²﹚
⑷2x²-3 [2x-2﹙-x²+2x-1﹚-4]

化简:⑴(x²-y²) -4 (2x²-3y)
=x²-y²-8x²+12y
=-7x²-y²+12y
⑵4x-3﹙1-3/2x﹚+4﹙2-x/4﹚
=4x-3+9/2x+8-x
=15/2x+5
⑶3﹙a²-2ab﹚-2﹙-3ab+b²﹚
=3a²-6ab+6ab-2b²
=3a²-2b²
⑷2x²-3 [2x-2﹙-x²+2x-1﹚-4]
=2x²-3(2x+x²-4x+2-4)
=2x²-3x²+6x+6
=-x²+6x+6嗯嗯,还有几题不会!!!求求你了!!!!!%>_