# Quadratic equations

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• August 11th 2011, 06:47 AM
drewm
Quadratic equations
I'm stuck on a few problems and was hoping I could get some help.

x^2=4-2x

the answer key says x=-1 plus or minus √5 but I have not been able to come to this.

Also,

2x^(2/3)-5x^(1/3)=3
• August 11th 2011, 06:52 AM
anonimnystefy
Re: Quadratic equations
hi drewm

for the first one,move all of the terms to one side.then use the quadratic formula to get x.

for the second one use the substitution t=x^(1/3),then move all of the terms to one side,use the quadratic formula to get t and calculate x from t.
• August 11th 2011, 07:12 AM
drewm
Re: Quadratic equations
I am kind of stuck on the second one, mainly factoring this:

2u^2-5u-3=0 ?
• August 11th 2011, 07:14 AM
e^(i*pi)
Re: Quadratic equations
Trial and error leads us to $(2u + 1)(u-3)$