the first step is to find the determinant of the matrix:
using ad-bc you get (-1*3) - (-5*5) = = -1*3 + 5*5 = 22
now the numbers inside the matrix become fractions with the determinant as the denominator
so you get -1/22, 5/22, -5/22 and 3/22
and replace them in reverse order
3,22, -5/22 , 5/22, -1/22
