若(x+y-5)^2+lx-y+3l=0,则 x^2-y^2=?,现在回答,

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若(x+y-5)^2+lx-y+3l=0,则 x^2-y^2=?,现在回答,

若(x+y-5)^2+lx-y+3l=0,则 x^2-y^2=?,现在回答,
若(x+y-5)^2+lx-y+3l=0,则 x^2-y^2=?,现在回答,

若(x+y-5)^2+lx-y+3l=0,则 x^2-y^2=?,现在回答,
(x+y-5)^2+lx-y+3l=0,
x+y-5=0 x-y+3=0
x+y=5 x-y=-3
x^2-y^2=(x+y)(x-y)=5*(-3)=-15

(x+y-5)^2+lx-y+3l=0
x+y=5
x-y=-3
x=1 y=4
所以x^2-y^2=-15

lx-y+3l=0
(x+y-5)^2=0
x+y-5=0
x-y+3=0
x-y=-3
x+y=5
x=1
y=4
所以x^2-y^2=-15

x+y-5=0
x-y+3=0
x=1 y=4
x^2-y^2= -15

x+y-5=0
x-y+3=0
解方程,得x+y=5,x-y=-3
x^2-y^2=(x+y)(x-y)=-15

答案=-15
因为 平方数与绝对值为非负数
又因为 此算式等于0
所以 X+Y-5=0 X-Y+3=0
X+Y=5 X-Y=-3
所以 X^2+Y^2=(X+Y)(X-Y)=5乘以-3等于-15

这里你首先要知道两个非负数相加的和为零,那么必是零加零,所以X+Y-5=0,X-Y+3=0,就可以解出X=1,Y=4,那么X^2-Y^2=-15