Fourier trans. help me

Π(3t/2) e-5t sign of the supposed plot to find the Fourier transform my will code

Fs = 150; % Sampling frequency
t = -0.5:1/Fs:0.5; % Time vector of 1 second
w = .3/2; % width of rectangle
x = rectpuls(t ,w); % Generate Square Pulse
nfft=512;
k=x.*exp(-5*t);
X=fft(k,nfft);
X=X(1:nfft/2);
mx=abs(X);
f=(0:nfft/2-1)*Fs/nfft;
subplot(2,1,1);
plot(t,k);
subplot(2,1,2);
plot(f,mx);

I do not know if this code is correct

How do I find sweat and fourier transform of the signal

Π((f-300)/2)+ Π((f-300)/2)

thank you :)