Find s4 when sn=28-7n S=

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 .

Solve the equation using the given values: x= -2.5; y= -7.51. 2xy + 2x²

What is the equation of a line passing through (-6,5) and having a slope of 1/3