SOLUTION: The demand and supply equations for a certain item are given by D = 5p + 40 S= -p^2 + 30p -8 Find the equilibrium Price. The answer I got for this one was $1.29. Is this corr

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: The demand and supply equations for a certain item are given by D = 5p + 40 S= -p^2 + 30p -8 Find the equilibrium Price. The answer I got for this one was $1.29. Is this corr      Log On


   

Question 76414: The demand and supply equations for a certain item are given by
D = 5p + 40
S= -p^2 + 30p -8
Find the equilibrium Price.
The answer I got for this one was $1.29. Is this correct? The answer options to this question are:
A)$1.29
B)$1.43
C)$1.57
D)$1.71
Thanks for all your help with this.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
D = 5p + 40
S= -p^2 + 30p -8
Find the equilibrium Price.
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Equilibrium means demand equals supply.
EQUATION:
5p+40 = -p^2+30p-8
p^2-25p+48=0
p=[25+-sqrt(625-4*48]/2
p=[25+-20.8]/2
p=$2.10 or $22.90
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Cheers,
Stan H.