factor.\n$z^2 - 12z + 20$

Explanation:

Step1: Find two numbers

We need two numbers that multiply to (20) and add up to (-12). The numbers are (-10) and (-2) since ((-10)\times(-2) = 20) and (-10 + (-2)=-12).

Step2: Factor the quadratic

Using the numbers from Step 1, we can factor (z^{2}-12z + 20) as ((z - 10)(z - 2)).

Answer:

((z - 10)(z - 2))