Identify Factoring Type: Identify the type of factoring required for the expression 1−z9. The expression is a difference of two terms, and since one of the terms is 1, which is a perfect square (12), and the other term is z9, which can be written as (z3)3, we can recognize this as a difference of cubes: a3−b3.
Apply Difference of Cubes: Apply the difference of cubes formula to factor the expression.The difference of cubes formula is a3−b3=(a−b)(a2+ab+b2). Here, a=1 and b=z3.So, 1−z9=(1−z3)(12+1⋅z3+(z3)2).
Simplify Factored Expression: Simplify the factored expression.1−z9=(1−z3)(1+z3+z6).
Recognize Simplified Term: Recognize that the term 1+z3+z6 is already simplified and cannot be factored further using real numbers.The expression 1+z3+z6 does not have any common factors, nor does it fit any special factoring formulas such as difference of squares or sum/difference of cubes.
Write Completely Factored Form: Write down the completely factored form of the original expression.The completely factored form of 1−z9 is (1−z3)(1+z3+z6).
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