This is a interesting problem:

(-5)^2 * -5^3

= -5^2+3

= -5^5

Using the calculator, both (-5)^2 * -5^3 and -5^5 is -3125.

Now, consider this:

(-2)^3 * 2^5

= -2^3+5

= -2^8

Using the calculator again, we have different results:

(-2)^3 * 2^5 = -8 * 32 = -256

-2^8 = 256

The original is negative and the simplified expression is positive. It looks like the expression cannot be simplified, but why??

Please help. Thanks.