solving K= (x-3)^2 / (x + 4.5)^3 (1.5) for x

[luna]

Hello Experts!

Help! I need help isolating x so that I can solve this problem (probably by quadratic formula)....

(K is a constant that I know the value for)

K= (x-3)^2 / (x + 4.5)^3 (1.5)

I know to expand the numerator....not too sure how to factor or otherwise cope with the denominator.
Thanks!!

 

[stapel]

Note: The expression (x + 4.5)[sup:37gxu79u]3[/sup:37gxu79u] is already in factored form. Perhaps you meant "multiply it out"...?

K= (x-3)^2 / (x + 4.5)^3 (1.5)

Is the "1.5" part of the numerator or the denominator? How far have you gotten in expanding and simplifying the fraction?

Thank you!

Eliz.

 

[luna]

The 1.5 is in the denominator. I expanded the numerator, no problem. I just don't know what to do with the cubed term so that I can solve for x....I was thinking it would involve a quadratic so I was trying to arrange the problem in standard form.

 

[stapel]

I was thinking it would involve a quadratic so I was trying to arrange the problem in standard form.

You'd have to solve the entire equation for "x=", not just a quadratic portion of it. Since the denominator is clearly going to be a cubic, I'm not sure how you're trying to bring the Quadratic Formula to bear...? :shock:

What have you been taught about solving cubics symbolically? (There is a formulaic method, but it's very messy.)

Eliz.