Consider the graph of the function

Question

f (x) = x2 − x − 30
.
(a) Find the equation of the secant line joining the points (−4, −10), and (6,0).

Answer 1

the slope of the line is (0+10)/(6+4) = 1
So, now use the point-slope form of the line. Pick either point, and you get
y+10 = 1(x+4)
or y+0 = 1(x+6)
either way you get y=x+6

Note that the function mentioned is irrelevant. You just need the two points.