2
6
16.7
2-19
2. (1)承上題,若2-b=/21+k/5,k為整數,則k值為
。
(2) 承(1),若/21+kV5+/21-KV/5 為有理數,則此有理數為何?(計算)
8
81
21
(U)
9-510 74 15-214x5 = √(5-14) = JS-2'≈0.
a=0
$17+14 51-4116
1-51=9
=528442
平方
> b= √m + kB 74-15 = 11+13 + 16-5-815=21+ 1/5
172/16
k=-8
(2) | 7 |- (13 + 24855 = [(4-13) " + √4 +1)² = (4-15) + (4+15) = =
感謝( ̄^ ̄)ゞ