题目内容
求代数式的值:
(1)当a=3,b=-
时,求代数式a2+2ab+b2的值;
(2)已知2011x+2012y-1=0,若x,y互为相反数,求x2011•y的值.
(1)当a=3,b=-
1 |
2 |
(2)已知2011x+2012y-1=0,若x,y互为相反数,求x2011•y的值.
(1)当a=3,b=-
时,
a2+2ab+b2
=32+2×3×(-
)+(-
)2
=9-3+
=
;
(2)∵2011x+2012y-1=0,
∴2011(x+y)+y-1=0,
又x,y互为相反数,x+y=0,
∴y=1,x=-1,
∴x2011•y=-1.
1 |
2 |
a2+2ab+b2
=32+2×3×(-
1 |
2 |
1 |
2 |
=9-3+
1 |
4 |
=
25 |
4 |
(2)∵2011x+2012y-1=0,
∴2011(x+y)+y-1=0,
又x,y互为相反数,x+y=0,
∴y=1,x=-1,
∴x2011•y=-1.
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