九年级(初三)数学题

.（2+1)(2^2+1)(2^4+1)(2^8+1)(4-1)
=(2-1)（2+1)(2^2+1)(2^4+1)(2^8+1)(4-1)
=(2^2-1)(2^2+1)(2^4+1)(2^8+1)(4-1)
=(2^4-1)(2^4+1)(2^8+1)(4-1)
=(2^8-1)(2^8+1)(4-1)
=(2^16-1)*3
=65535*3
=196605

2.已知a-1/a=4,求a^2+1/a^2的值。

a-1/a=4
(a-1/a)^2=16
a^2+1/a^2-2=16
a^2+1/a^2=18

3.6^100*(1/2)^99*(1/3)^99

=6*6^99*(1/2*1/3)^99
=6*6^99*(1/6)^99
=6*(6*1/6)^99
=6*1
=6

4.如果x^2+kx+64是一个整式的平方，则常数K=?
(x±8)^2=x^2±16x+64
即k=±16

5.(x+3)(2x-m)的值不含一次项，则常数m=?

.(x+3)(2x-m)
=2x^2-mx+6x-3m
=2x^2+(6-m)x-3m(不含一次项)
即6-m=0
m=6

6.如果一个偶数k的立方根比2大，平方根比4小，则k=？

偶数m的立方根比2大,平方根比4小

就是说此数应该在:8----16之间.

即有:m=10,12,14

1.（2+1)(2^2+1)(2^4+1)(2^8+1)(4-1)
=（2+1)(2^2-1)(2^2+1)(2^4+1)(2^8+1)
=(2+1)(2^4-1)(2^4+1)(2^8+1)
=(2+1)(2^8-1)(2^8+1)
=(2+1)(2^16-1)
=3*(2^16-1)
2.已知a-1/a=4,求a^2+1/a^2的值