SOLUTION: If a < b, then -a > -b. Why?

From this we understand that a is smaller than b.

In other words,b is greater than a.

Now,
suppose a is 3,and b is 5.
then b is still great than a

3 < 5
a < b

-3 ? -5
Now think,which is the BIGGER number ... -3 or -5?
the bigger number is -3.

Suppose you have 60 candles.let that be Z.
z-a > z-b
Is the above statement true or false?

It is true,because
60-3 > 60-5

Hence,
if a < b
then -a > -b

Hope this helps