Question

化简求值:y(x+y)+(x+y)(x-y)-xy,其中x=-2

Answer 1

原式=xy+y²+x²-y²-xy
=x²
=(-2)²
=4

追问

计算:(x^2+1/2)^2

追答

=x^4+x²+1/4

追问

(a+b)^2=11(a-b)^2=1,求a^2+b^2

追答

采纳我，重新问

追问

好的！

Answer 2

y(x+y)+(x+y)(x-y)-xy
=[y+(x-y)](x+y)-xy
=x(x+y)-xy
=x²+xy-xy
=x²
=(-2)²
=4

追问

计算:(-x^2)(x+1)-(x+2)(x-1)

追答

(-x^2)(x+1)-(x+2)(x-1)
=-x³-x²-x²-x+2
=-x³-2x²-x+2

追问

a+b=9，ab=2,求a^2+b^2

追答

a²+b²
=(a+b)²-2ab
=9²-2*2
=81-4
=77

Answer 3

y(x+y)+(x+y)(x-y)-xy
=xy+y²+x²-y²-xy
=x²
=（-2）²
=4

追问

计算:(x^2+1/2)^2

追答

:(x^2+1/2)^2
=x^4+x²+1/4

追问

计算:(-x^2)(x+1)-(x+2)(x-1)

追答

(-x^2)(x+1)-(x+2)(x-1)
= -x^3-x²-x²-x+2
= -x^3-2x²-x+2

追问

(a+b)^2=11(a-b)^2=1,求a^2+b^2

追答

重新提问吧，太多了

Answer 4

y(x+y)+(x+y)(x-y)-xy=xy+y^2+x^2-y^2-xy=x^2=(-2)^2=4