Question 772016
Hi,

You started the problem brilliantly by setting R = C

6* SQRT(x) + 4000 = 4.9x

4.9x  - 6SQRT(x) - 4000 = 0

From here, you will treat SQRT(x) as Y. Then you rewrite the equation in Y

Since SQRT(x) = Y then x = Y^2

4.9Y^2 - 6Y - 4000 = 0

Solve for Y and choose positive Y only.

After you found Y, you will substitute Y = SQRT(x) and solve for x.

Hope it helps you!

John10 (john100185@yahoo.com)