问题 解答题

(1)请从三个代数式4x2-y2,2xy+y2,4x2+4xy+y2中,任选两个构造一个分式,并化简该分式;

(2)解方程:(x-1)2+2x-3=0.

答案

(1)本题答案不唯一.

4x2-y2
2xy+y2
(2分)

=

(2x+y)(2x-y)
y(2x+y)
(6分)

=

2x-y
y
(8分)

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

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

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

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

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

(2)x2-2x+1+2x-3=0(3分)

x2-2=0

x2=2(6分)

∴x1=

2
,x2=-
2
.(8分)

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