Question

Is this the X factor method and how would you do it?

Answer 1

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

• -8 + 6 = -2
• -8*6 = -48

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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)