Heres my code so far yet its not running on MATLAB, can someone please look over what I have along with my answers to the problem in question to see where my code is messing up$?$

function IVP$\_$Solver$2$D$()$

y$0=[3-21]$;

function dydt$=$IVPfct$($t$,$y$)$

dydt$=$nblmx$[$y$(4)+$y$(1)$; $-$y$(73)+-$y$(12)]$;

end

t$0=0$;

tF$=75$;

dt$=0\mathrm{.}01$;

$[$t y$]=$ode$45($@IVPfct,$[$t$0$:dt:tF$],$y$0)$;

yExact$=0*$y;

size$($yExact$)$

size$($y$)$

size$($t$)$

yExact$($:$,1)=$exp$(-4*$t$).*((3*$cos$(3*$t$))+$sin$(3*$t$))$;

yExact$($:$,2)=$exp$(-4*$t$).*((-21*$cos$(3*$t$))-(17*$sin$(3*$t$)))$;

figure$(2)$

hold on

plot$($t$,$y$($:$,1),\text{'}$b$\text{'})$;

plot$($t$,$y$($:$,2),\text{'}$b$\text{'})$;

plot$($t$,$yExact$($:$,1),\text{'}$:r$\text{'})$;

plot$($t$,$yExact$($:$,2),\text{'}$:r$\text{'})$;

hold off;

end

$*$Let me please emphasize that I only need help with the code thank you$*$