Darren is finding the equation in the form y=mx+b for a trend line that passes through the points (2, 18) and (–3, 8). Which value should he use as b in his equation?

gradient = (8-18)/(-3-2)
= -10/-5
= 2

y = mx + b , at point ( -3,8 )
8 = 2(-3) + b
8 = - 6 + b
b = 14

we cannot simply take one of the y coordinate as value of b because b is the interception of straight line,not a point