先化简,在求职:4(x的2次方+2y的2次方)-2(x的2次方-2xy+y的2次方)-2[x的2次方-(2xy-2y的2次方)] 要过程

其中,|x+3|+|3y-1|=0
2024-12-13 04:06:40
推荐回答(2个)
回答1:

∵|x+3|+|3y-1|=0
x+3>=0,3y-1>=0,
∴ x=-3,y=1/3

4(x²+2y²)-2(x²-2xy+y²)-2[x²-(2xy-2y²)]
= 4(x²+2y²)-2(x²-2xy+y²)-2(x²-2xy+y²)
=4(x²+2y²)-4(x²-2xy+y²)²
=4[x²+2y²-(x²-2xy+y²)]
=4(x²+2y²-x²+2xy-y²)
=4(y²-x²)
=4(y-x)(y+x)=-320/9
值不一定对,但化简结果应该是对的

回答2:

∵|x+3|+|3y-1|=0
∴x+3=0且3y-1=0
x=-3,y=1/3

4(x²+2y²)-2(x²-2xy+y²)-2[x²-(2xy-2y²)]
=4x²+8y²-2x²+4xy-2y²-2x²+2(2xy-2y²)
=4x²+8y²-2x²+4xy-2y²-2x²+4xy-4y²
=2y²+8xy
=2*(1/3)²+8*(-3)*1/3
=2/9-8
=-70/9