Answer: D. (x - 8)
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Work Shown:
4x^2 - 8x - 192
4(x^2 - 2x - 48)
4(x - 8)(x + 6)
We see that (x - 8) is one factor
To factor x^2-2x-48 into (x-8)(x+6), we need to find two numbers that
- add to -2, and
- multiply to -48
Through trial and error you should find the two values are -8 and 6 since
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Another approach is to use the quadratic formula to solve x^2-2x-48 = 0. You should find that the two roots are x = 8 and x = -6.
Those two roots lead to the equations x-8 = 0 and x+6 = 0.
Then use the zero product property to get (x-8)(x+6) = 0
This shows that x^2-2x-48 factors to (x-8)(x+6)
