Use the result for the gamma distribution to determine the mean and variance of a chi-square distribution

Question:

Use the result for the gamma to determine the mean and variance of a chi-square with r = 7/2.
Distribution
The word "distribution" has several meanings in the financial world, most of them pertaining to the payment of assets from a fund, account, or individual security to an investor or beneficiary. Retirement account distributions are among the most...