Robert's father is 5 years older than 3 times robert's age. let robert's age be denoted by r and let robert's father's age be denoted by f. write an equation that relates robert's age and his father's age.
how do i write an equation to fit this, can someone tell me the steps on how to do it?

Abilliard ball is struck by a cue. it travels 1 0 0 cm 100cm before ricocheting off a rail and traveling another 1 2 0 cm 120cm into a corner pocket. the angle between the path as the ball approaches the rail and the path after it strikes the rail is 4 5 ∘ 45 ∘ . how far is the corner pocket from where the cue initially struck the ball? do not round during your calculations. round your final answer to the nearest centimeter.