Quadratics: Factoring and Solving Quadratics Using FOIL
If $$(x-2\sqrt{3})$$ is one factor of the quadratic $$x^2+(4\sqrt3)x-36$$, what is the other factor?
Correct.
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Since $$(x-2\sqrt{3})$$ is a factor, you know that $$e = -2\sqrt{3}$$. _(Of course, it could be the case that $$f = -2\sqrt{3}$$, but $$e$$ and $$f$$ are interchangeable, so it doesn't matter which one you assign to the known value.)_
In the given quadratic, you can see that $$b$$, the coefficient of the $$x$$-term, is $$4\sqrt{3}$$. That gives you the equation:
> $$e+f = b$$
> $$-2\sqrt3 + f = 4\sqrt3$$.
Adding $$2\sqrt{3}$$ to both sides gives
> $$f = 6\sqrt3$$.
Thus, the other factor is $$x+f = x+6\sqrt3$$.
Incorrect.
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Make sure you find a factor so that $$e+f = 4\sqrt{3}$$.
Incorrect.
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Carefully check your calculations.
Incorrect.
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You might have gotten this answer if you made a sign error.
Incorrect.
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You need to find a factor so that $$e+f = 4\sqrt{3}$$.
$$x+2\sqrt{3}$$
$$x+4\sqrt{3}$$
$$x+6\sqrt{3}$$
$$x-2\sqrt{3}$$
$$x-6\sqrt{3}$$