How can I solve this system of equations?

I have the following equations and am trying to solve for 'L'?

D = (kT/3*pi*eta*L)*(ln(p) + v)

where p = L/d & v = 0.312 + 0.565/p + 0.100/p^2

D, k, T, eta, & d are known. Need to solve for L.

When I try to store eq's p and v in order to plug into eq D I get errors of undefined variables or functions. Is there a way to take eq's p and v, and put them into eq D and solve for 'L'?

Answer 1

[Roger Stafford]

Solve kT/3*pi*eta*L*(ln(L/d)+0.312+0.565/(L/d)+0.100/(L/d)^2) for L.