Anyone good at composite functions? ?

Solve 2x+y=3 x+y=5 in substitution method

Sue's average score for three bowling games was 162. in the second game, sue scored 10 less than in the first game. in the third game, she scored 13 less than in the second game. what was her score in the first game?

Present age of man is 45 years, 5 years back his age was 4 times age of his son what is present age of his son?