题目内容
(1)计算:3(
+
)-(
+
).
(2)已知:x=
+1,y=
-1,求代数式x2+2xy+y2的值.
2 |
3 |
8 |
27 |
(2)已知:x=
2 |
2 |
(1)原式=3
+3
-2
-3
=
(3-2)+
(3-3)=
.
(2)x2+2xy+y2=(x+y)2=(
+1+
-1)2=(2
)2=8,即代数式x2+2xy+y2的值为8.
2 |
3 |
2 |
3 |
2 |
3 |
2 |
(2)x2+2xy+y2=(x+y)2=(
2 |
2 |
2 |
练习册系列答案
相关题目