What is the constant of proportionality in the equation y= 5/4x plz answer !

The equation respenting the left table is

Plot the points (0,6), (3,15.8), and (9.5,0) using the graphing tool, and find the function

Tomas is making trail mix using granola and walnuts. he can spend a total of $12 on the ingredients. he buys 3 pounds of granola that costs $2.00 per pound. the walnuts cost $6 per pound. he uses the equation to represent the total cost, where x represents the number of pounds of granola and y represents the number of pounds of walnuts. he solves the equation for y, the number of pounds of walnuts he can buy. answer- b tomas added 6 to both sides of the equation instead of subtracting 6. just took the test