Example 8:  Factor 3x² – 48

Solution:  3x² and 48 are not perfect squares, but both have 3 as a common factor.  Therefore we start by factoring out 3:

3x² – 48 = 3(x² – 16)

Now x² – 16 is the difference of squares, so it can be factored:

3x² – 48 = 3(x² – 16) = 3(x – 4)(x + 4)

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