Algebraic Equation Solver with Unwanted Solutions

Im trying to solve this 2 equations but I get an output with 4 diferents solutions when I need just 1 for each variable

m = 14.8; % mass of solar panel in Kg
t = 5; % time of deployment in seconds
Theta = 1.5708; % displacement of mechanism in radians
r = 0.909; % radius of the rotational trajectory
I = (1/3)*m*(r^2); % mass moment of inertia
Alpha = (2*Theta)/t^2;
T = Alpha*I; % torque
E = 207000000000; % N/m^2
Di = (0.007*1.1);
n = 0.25; 
N = 4.25;
k = T/n;
syms Dm d 
eqn1 = Dm == Di + d;
eqn2 = k == (d^4*E)/(10.8*N*Dm);
solution = solve([eqn1,eqn2] , [Dm,d]);
DmSol = double((solution.Dm)) 
dSol = double((solution.d))

Can someone explain me the error?

Answer 1

[Walter Roberson]

eqn2 = k == (d^4*E)/(10.8*N*Dm);

You have a polynomial in d^4. It is going to have 4 solutions.

You can filter out complex values by adding 'real', true option to solve(). But that will still give you an even number of solutions.