2x的平方+4xy+5y的平方-4x+2y+5=0
(x+2y)^2+(x-2)^2+(y+1)^2=0
∵(x+2y)^2≥0,(x-2)^2≥0,(y+1)^2≥0
∴(x+2y)^2=0,(x-2)^2=0,(y+1)^2=0
x=2,y=-1
(3x的平方y)的平方*(-8/3xy的立方)除以(-4x的四次方y的2次方)
=9x^4y^2*(-8/3xy^3)/(-4x^4y^2)
=24x^5y^5/(4x^4y^2)
=6xy^3
=-12
2x的平方+4xy+5y的平方-4x+2y+5=0
(x+2y)^2+(x-2)^2+(y+1)^2=0
∵(x+2y)^2≥0,(x-2)^2≥0,(y+1)^2≥0
∴(x+2y)^2=0,(x-2)^2=0,(y+1)^2=0
x=2,y=-1
(3x的平方y)的平方*(-8/3xy的立方)除以(-4x的四次方y的2次方)
=9x^4y^2*(-8/3xy^3)/(-4x^4y^2)
=24x^5y^5/(4x^4y^2)
=6xy^3
=-12