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Mathematics 24 Online
OpenStudy (destinyyyy):

Help..

OpenStudy (destinyyyy):

Find the real solutions of the equation. 4x^2/3 -11x^1/3 -3=0

OpenStudy (destinyyyy):

@Nnesha @IrishBoy123

OpenStudy (campbell_st):

ok.. so this is an equation that can be written as a quadratic use a substitution \[u = x^{\frac{1}{3}}\] so the equation is \[4u^2 - 11u - 3 = 0\] this can be factored to (4u + 1)(u - 3) = 0 so then solve for u... does that make sense so far...?

OpenStudy (destinyyyy):

So I can do substitution? Okay

OpenStudy (campbell_st):

yes... that is the easiest method to solve this equation when you get the solutions for u, then let the solutions equal \[x^{\frac{1}{3}}\]

OpenStudy (campbell_st):

then you can solve for x

OpenStudy (destinyyyy):

Yes I know that.. I assumed I couldn't solve that way since it didnt say I could

OpenStudy (destinyyyy):

u= -1/4 and u= 3

OpenStudy (campbell_st):

well it will give the real solutions... I'd always treat questions of this type as quadratics.... so you need to solve \[x^{\frac{1}{3}} = -\frac{1}{4},~~and~~~~, x^{\frac{1}{3}} = 1\]

OpenStudy (destinyyyy):

So x= 32 and 27 correct?

OpenStudy (destinyyyy):

Oops. -1/64, 27

OpenStudy (campbell_st):

yes that's a lot better

OpenStudy (destinyyyy):

Thank you.

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