Without the use of appropriate symbols and parentheses, it is hard to tell what the problem is. We think you might be trying to simplify
2·a²b·(-2·ab³)⁻²
= 2·(-2)⁻²·a²·a⁻²·b·b⁻⁶
= 2/(4b⁵)
= 1/(2b⁵)
If so, this would mean neither Alejandra nor Kyle is correct.
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First of all, look at the constants. It appears you have a multiplier of 2 at the front, and a multipier of -2 inside parentheses that are raised to the -2 power. The product of these is 2^(1-2) = 1/2. If Kyle's answer is (ab^7)/2, then the constant is correct. As is, Kyle's answer looks like a·b^(72), which is clearly incorrrect.
