Question

先化解后求值4xy-(2x^2+5xy-y^2)+2(x^2+3xy),其中|x+2|+(y-1/2)^2=0

Answer 1

|x+2|+(y-1/2)^2=0
∴x+2=0
y-1/2=0
∴x=-2
y=1/2

4xy-(2x^2+5xy-y^2)+2(x^2+3xy)
=4xy-2x²-5xy+y²+2x²+6xy
=5xy+y²
=5*（-2）*1/2+(1/2)²
=-5+1/4
=-19/4

Answer 2

y^2+5xy 值是 -19/4

Answer 3

先求得X=-２，Y=１/2;原式化简为5xy+y^2=-4.5;