填空1.(3x-1)(4x+5)2.(-4x-y)(-5x+2y)3.(x+3)(x+4)-(X-1)(X-2)4.(y-1)(y-2)

问题描述:

填空1.(3x-1)(4x+5)2.(-4x-y)(-5x+2y)3.(x+3)(x+4)-(X-1)(X-2)4.(y-1)(y-2)

1.(3x-1)(4x+5)=12x²+11x-52.(-4x-y)(-5x+2y)=20x²-3xy-2y²3.(x+3)(x+4)-(X-1)(X-2)=x²+7x+12-x²+3x-2=10x+104.(y-1)(y-2)=y²-3y+2