Please give a detailed step-by-step answer for this one problem. For prep in 210. I am struggling, thank you.

Problem 2 (a) Consider two random variables X1 and X2 whose joint probability density function is if0x12and0xggl l fX|,X2(-'C1ax2)={ 4, 0, otherwise Determine the probabilities (i) P(X1 1); (iii) P(X1 = X2). (b) Consider two random variables X1 and X2 whose joint probability density function is e(x1+x2)' if 0 3 x1