(5a²-3b²)-3(a²-b²)-(-b²),其中a=5,b=-35x²-(3y²+5x²)+(4y²+3xy),其中x=-1,y=1/3计算:2x²y+{2xy-[3x²y-2(-3x²y+2xy)]-4xy²}
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(5a²-3b²)-3(a²-b²)-(-b²),其中a=5,b=-35x²-(3y²+5x²)+(4y²+3xy),其中x=-1,y=1/3计算:2x²y+{2xy-[3x²y-2(-3x²y+2xy)]-4xy²}
(5a²-3b²)-3(a²-b²)-(-b²),其中a=5,b=-3
5x²-(3y²+5x²)+(4y²+3xy),其中x=-1,y=1/3
计算:2x²y+{2xy-[3x²y-2(-3x²y+2xy)]-4xy²}
(5a²-3b²)-3(a²-b²)-(-b²),其中a=5,b=-35x²-(3y²+5x²)+(4y²+3xy),其中x=-1,y=1/3计算:2x²y+{2xy-[3x²y-2(-3x²y+2xy)]-4xy²}
1、(5a²-3b²)-3(a²-b²)-(-b²)
=5a²-3b²-3a²+3b²+b²
=2a²+b²
当a=5,b=-3时
原式=50+9=59
2、5x²-(3y²+5x²)+(4y²+3xy),
=5x²-3y²-5x²+4y²+3xy
=y²+3xy
当x=-1,y=1/3时
原式=1/9-1=-8/9
计算:2x²y+{2xy-[3x²y-2(-3x²y+2xy)]-4xy²}
=2x²y+2xy-3x²y-6x²y+4xy-4xy²
=-7x²y+6xy-4xy²