How to find MME and MLE in a Negative Exponential distribution

Hi guys, I'm new here, so if anything is wrong with my post please do tell me. I was going through some of the tutorial questions from last week (I am currently doing Statistics in my 2nd year), when I found a question that asked me to find the Method of Moments Estimator and the Maximum Likelihood Estimator of a Negative Exponential distribution. Since we only get the answers for a few of our tutorial questions, and this was not one of them, I tried to figure this out, but I could not find anyting in my lecture notes or the internet. Since I am not sure if I can just put the exact question in I'll just ask for something more general: Lets say the probability density function is fx(x;delta)= e^(-x/delta) / delta mean= E(x) = delta and var(x)= delta² How could I find the MME and MLE for this distribution, since I have no idea where to start at? PS: Sorry for the poor display