问题
解答题
有这样一道题:计算
|
答案
原式=
+(x+
)2x2-4 (x-
)(x+x2-4
)x2-4
-x2(x-
)2x2-4 (x-
)(x+x2-4
)x2-4
=
+x2+x2-4+2 x2-4 x2-x2+4
-x2x2+x2-4-2 x2-4 x2-x2+4
=
-x2=-2.4x2-8 4
∵化简结果与x的值无关,
∴该同学虽然抄错了x的值,计算结果却是正确的.
有这样一道题:计算
|
原式=
+(x+
)2x2-4 (x-
)(x+x2-4
)x2-4
-x2(x-
)2x2-4 (x-
)(x+x2-4
)x2-4
=
+x2+x2-4+2 x2-4 x2-x2+4
-x2x2+x2-4-2 x2-4 x2-x2+4
=
-x2=-2.4x2-8 4
∵化简结果与x的值无关,
∴该同学虽然抄错了x的值,计算结果却是正确的.