Break-even analysis: don't know how to solve w/ square root

AGlas9837

Junior Member
Joined
Jan 23, 2008
Messages
57
The objective of this problem is to find the sales necessary to break even for the given cost and revenue equations.

Cost = 5.5sqrt(x) + 10,000; Revenue = 3.29x

This is what I've done so far:

3.29x = 5.5sqrt(x) + 10,000
3.29x-5.5sqrt(x) = 10,000

I'm stuck after this, not understanding how to substract the 5.5 square root part.
 

stapel

Super Moderator
Staff member
Joined
Feb 4, 2004
Messages
15,943
AGlas9837 said:
I'm stuck after this, not understanding how to substract the 5.5 square root part.
To learn how to solve radical equations, please study some of the many great lessons available online:

. . . . .Google results for "solving radical equations"

Once you have studied some lessons (at least two!), please attempt the exercise. If you get stuck, or if you are unsure of your steps or solution, please reply clearly showing your work and reasoning. Thank you! :D

Eliz.
 

PAULK

Junior Member
Joined
Dec 13, 2007
Messages
124
AGlas9837 said:
The objective of this problem is to find the sales necessary to break even for the given cost and revenue equations.

Cost = 5.5sqrt(x) + 10,000; Revenue = 3.29x

This is what I've done so far:

3.29x = 5.5sqrt(x) + 10,000
3.29x-5.5sqrt(x) = 10,000

I'm stuck after this, not understanding how to substract the 5.5 square root part.
Try this: Let y = sqrt(x). Then x = y^2. You now have:

3.29y^2 - 5.5y = 10000,

a quadratic equation.
 
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