已知x눀+y눀+13-4x+6y=0,求(2x-y)눀-2(2x-y)(x+2y)+(x+2y)눀的值

2026年09月22日 23:09
有4个网友回答
网友(1):

x²+y²+13-4x+6y=0
(x²-4x+4)+(y²+6y+9)=0
(x-2)²+(y+3)²=0
平方项恒非负,两非负项之和=0,两非负项分别=0
x-2=0 x=2
y+3=0 y=-3

(2x-y)²-2(2x-y)(x+2y)+(x+2y)²
=[(2x-y)-(x+2y)]²
=(x-3y)²
=[2-3·(-3)]²
=11²
=121

网友(2):

x²+y²+13-4x+6y=0
(x-2)²+(y+3)²=0
x=2,y=-3

(2x-y)²-2(2x-y)(x+2y)+(x+2y)²
=【(2x-y)-(x+2y)】²
=(x-3y)²
=【2-3×(-3)】²
=11²
=121

网友(3):

x²+y²+13-4x+6y=0
(x-2)²+(y+3)²=0
x=2,y=-3
(2x-y)²-2(2x-y)(x+2y)+(x+2y)²
=[(2x-y)-(x+2y)]²
=(x-3y)²
=11²
=121

网友(4):