The equation of a linear function is y=mx+b
The point is to calculate b, since m is given (slope=-1/5) & x & y are given x=0 & y=6 [from the intercept value that is (x=0, & y=6). Plug in: y=mx+b
6=(-1/5) x (0) +b ===> b=6
& the final equation is y=(-1/5)x + 6