问题
解答题
(1)先化简,后求值(
(2)小明做题时,把x=-
|
答案
(1)原式=[
+(x-2)2 (x+2)(x-2)
]÷4x (x+2)(x-2) 1 (x+2)(x-2)
=
•(x+2)(x-2)x2-4x+4+4x (x+2)(x-2)
=x2+4;
当x=-
时,原式=(-3
)2+4=7.3
(2)当x=
时,原式=(3
)2+4=7,结果与正确结果一样.3
(1)先化简,后求值(
(2)小明做题时,把x=-
|
(1)原式=[
+(x-2)2 (x+2)(x-2)
]÷4x (x+2)(x-2) 1 (x+2)(x-2)
=
•(x+2)(x-2)x2-4x+4+4x (x+2)(x-2)
=x2+4;
当x=-
时,原式=(-3
)2+4=7.3
(2)当x=
时,原式=(3
)2+4=7,结果与正确结果一样.3