How to find the intersection of a semi-log and a linear graph?

Hello,

I have the following code and cannot find the intersection of three graphs.

I highly appreciate any solutions to this matter.

Thank you in advance.

Regards,

clear
clc
Fr=20000;
Fsw=1000:100:200000;
Fx=Fsw/Fr;
m=5:1:8;
Q=0.01:0.01:5;
Kmax=1.0666666666;
Kmin=0.82727272727;
% plotting the gain of LLC resonant tank for different m,Q, and Fx
%% m=2
m=2;
figure
for i=1:length(Q)
    for j=1:length(Fx)
    K(j)=((Fx(j)^2)*(m-1))./sqrt((((m*(Fx(j)^2)-1))^2)+(Fx(j)^2)*(((Fx(j)^2)-1)^2)*((m-1)^2)*(Q(i)^2));
    end
 semilogx(Fx,K);
 semilogx(xlim, Kmax*[1 1]);
 semilogx(xlim, Kmin*[1 1]);
 grid on
 title("LLC Gain for m=2")
 xlabel("Fx")
 ylabel("LLC Gain")
 hold on
end
hold off

[darova]

Try polyxpoly