(先化简,再求值) (2x+3y)²-(2x+y)(2x-y),其中x=1/3,y=-1/2.

2024-12-04 11:17:17
推荐回答(1个)
回答1:

解:(2x+3y)²-(2x+y)(2x-y)
=(2x+3y)²-(4x²-y²)
=4x²+12xy+9y²-4x²+y²
=10y²+12xy
把x=1/配并哪3,y=培码-1/2代入10y²+12xy
10y²+12xy
=10*1/4+12*3分之1*负的2分蔽棚之1
=2.5-2
=0.5
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