问题
解答题
(1)已知a=8,b=-2,求[a-
(2)已知x
|
答案
(1)[a-
b(ab-2)-1 2
(a-1)-1 2
]2=[a-2 3
-1 2
+1 2
•b1+1]2=a-2 3
b4=4;2 3
(2)①∵x
+x-1 2
=31 2
平方得x+x-1+2=9
∴x+x-1=7
②x
+x-3 2
+23 2 x2+x-2+3
=(x
+x-1 2
)(x-1+x-1)+21 2 (x+x-1)2+1
=3×6+2 49+1
=2 5