How to solve this equation in Slope intercept form, to represent the relationship of values given in each table.

x: 3, 6, 10, 13, 15
y: -1, -7, -15, -21, -25

Using the first two points (3,-1) and (6,-7)

slope = (-7+1)/(6-3) = -2

let y = -2x + b
using (3,-1)
-1 = -6 + b
b = 5

equation: y = -2x + 5
test it for the other given points (10,-15), (13,-21) and (15, -25)