-2,3,8,13 write an equation for the “nth” term of each arithmetic sequence

Iam trying to solve a linear equation for the shoe size of someone 84" tall taking into consideration example 1 is 69" tall with a shoe size of 9 and example 2 is 72 inches tall with a shoe size of 11. i understand that the equation should be y=mx+b and that on the graph the answer is (3,2) but i just don't understand how to create the equation to solve for 84-inches and 60-inches tall questions. after two days, i need .

Which expression will have the same sum as 3_8 + 1/4?

45% of the trees in a park are apple trees. there are 27 apple trees in the park. how many trees are in the park in all?