Select the approximate values of x that are solutions to f(x)=0, where f(x)=-9x^2+5x+7

A. (1.20,-0.65)

B. (-9,5)

C. (-0.56,-0.78)

D. (-1.29,0.71)

Select the approximate values of x that are solutions to f(x)=0, where f(x)=-9x^2+5x+7

A. (1.20,-0.65)

B. (-9,5)

C. (-0.56,-0.78)

D. (-1.29,0.71)

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Katy, TX

I find that having the (-) on the x^{2} can sometimes make the quadratic formula confusing, as having the correct sign on the a,b, and c values is critical to get the correct answer. Multiply the whole equation by -1 and give the quadratic equation another shot!

The discriminant: b^{2 }- 4*a*c is also a very helpful tool for solving polynomials.

Hope this helps!

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