Factor ^2 - 4x + 4.
x^2 - 4x +4=

This is the same as

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Explanation:

The middle coefficient is -4 and the last term is 4.

We need to find factors of the last term that add to the middle coefficient.

Here is a list of all ways to multiply two integers to get 4, and the sum of each pair of factors.

The second row of that list above is what we're after. So

-2 + (-2) = -4

-2 * (-2) = 4

Meaning the factorization is (x-2)(x-2). Note the "-2" values in each factor

We can use the FOIL rule or distribution to go from (x-2)(x-2) back to x^2-4x+4 to confirm the answer.