Three question which needs to be answered it was little confusing for me thank you

1 ) find the functions From f ( * ) = * 2 + 3 ; g ( x ) - 5 x + 31 find : f + g = f - 9 - 2 ) find equation of the line that passes through the points ( 2, 0 ) and ( 3 , 3 ) 3) find the domain of the function ( answer with interval notation f ( x ) = 5 x - 14 1