已知a2-4a+b2-b/2+65/16=0,则a2-4b=_.
问题描述:
已知a2-4a+b2-
+b 2
=0,则a2-465 16
=______.
b
答
∵a2-4a+b2-
+b 2
=0,65 16
a2-4a+4+b2-
+b 2
=0,1 16
(a-2)2+(b-
)2=0,1 4
∴a-2=0,b-
=0,1 4
∴a=2,b=
,1 4
∴a2-4
=22-4
b
=4-2=2.
1 4
故答案为:2.