请教几个数学题

1、If n is a positive interger and r is the remainder when (n-1)(n+1)is divided by 24, what is the value of r?

(1)2 is not a factor of n

(2)3 is not a factor of n.

DS题，请教各位高手，谢谢！

2、Last year the price per share of Stock X increased by k percent and the earnings per share of Stock X increased by m percent, where k is greater than m. By what percent did the ratio of price per share to earnings per share increase, in terms of k and m?

3, 画了一个三角形，像直角。abc分别是三条边，c斜边，x写在图形中间，估计是面积。

In the triangle above, is X>90？

（1）a平方+b平方<15

（2）c>4

4, If line k in the xy-plane has equation y=mx+b, where m and b are constants, what is the slope of k?

(1)k is paralle to the line with equation y= (1-m)x+b+1

(2)k intersects the line with equation y=2x+3 at the point(2,7)

第一题选E吧，带个5进去看下就知道了。

第二第三题好奇怪，第四题选A吧。是parallel吧