问题 解答题
(1)
0.5
+
8
2
-
50

(2)(
48
-3
1
3
3

(3)(2
5
-1)2

(4)(x+y)(
x
+
y
)(
x
-
y
)
答案

(1)原式=

2
2
+
2
-5
2

=-

7
2
2

(2 ) 原式=(4

3
-
3
)÷
3

=3

3
÷
3

=3;

(3)原式=(2

5
2-2×2
5
+1

=20-4

5
+1

=21-4

5

(4)原式=(x+y)[(

x
2-(
y
2]

=(x+y)(x-y)

=x2-y2

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