问题
解答题
(1)
(2)(
(3)(2
(4)(x+y)(
|
答案
(1)原式=
+2 2
-52 2
=-
;7 2 2
(2 ) 原式=(4
-3
)÷3 3
=3
÷3 3
=3;
(3)原式=(2
)2-2×25
+15
=20-4
+15
=21-4
;5
(4)原式=(x+y)[(
)2-(x
)2]y
=(x+y)(x-y)
=x2-y2.
(1)
(2)(
(3)(2
(4)(x+y)(
|
(1)原式=
+2 2
-52 2
=-
;7 2 2
(2 ) 原式=(4
-3
)÷3 3
=3
÷3 3
=3;
(3)原式=(2
)2-2×25
+15
=20-4
+15
=21-4
;5
(4)原式=(x+y)[(
)2-(x
)2]y
=(x+y)(x-y)
=x2-y2.