两道prep maths DS向各位请教！

167. 

If x, y, and z are
integers and xy + z is an odd integer, is x an even integer?

(1) xy + xz is an
even integer.

(2) y + xz is an
odd integer.

A

168. 

On the number line,
the distance between x and y is greater than the distance between x and z.  Does z lie between x and y on the number
line?

(1) xyz < 0

(2) xy < 0

E

这两题看上去好复杂啊，如果真的考时碰到，看样子只能放弃了

有没有好的方法呢？

希望各位G友相助！

谢谢！