Question

数学高手请进！！求助！！选择填空答案！解答题要详细过程 求助

Answer 1

(1)4(x-y)^2-16(x+y)^2
=4(x-y)(x+y)-16(x+y)(x+y)
=4(x+y)(x-y-4x-4y)
=4(x+y)(-3x-5y)
=-4(x+y)（3x+5y)
(2)x^3-xy^2+x^2y-y^3
=x^2(x+y)-y^2(x+y)
=(x+y)(x^2-y^2)
=(x+y)^2(x-y)
(3)1/4(x-y)^2+x-y+1
=[1/2(x-y)+1]^2

2\
a(a+1)-(a^2+2b)=1
a^2+a-a^2-2b=1
a-2b=1

a^2-4ab+4b^2-2a+4b
=(a-2b)^2-2(a-2b)
=1^2-2*1=-1

3、a^2+2ab=c^2+2bc
a^2+2ab+b^2=c^2+2bc+b^2
(a+b)^2=(c+b)^2
a=c
等腰三角形