Answer: (a-b+2)x(a+b-2)
Explanation:
1) factor out the negative sign from the expression: a^2(b^2-4b+4)
2) Using a^2-2ab+b^2=(a-b)^2, factor the expression: a^2-(b-2)^2
3) Using a^2-b^2=(a-b)(a+b), factor the expression: (a-(b-2))x(a+(b-2))
4) When there is a - in front of an expression in parentheses, change the. Sign of each term in the expression: (a-b+2)x(a+(b-2))
5) When there is a + in front of an expression in parentheses, the expression stays the same: (a-b+2)x(a+b-2)