How do you solve this?

Question

Given f(x)=x^3-2, find the equation of the secant line passing through (-4,f(-4)) and (2,f(2))

Answer 1

f(-4) = (-4)^3-2 = -64-2 = -66

f(2) = 2^3-2 = 8-2=6

the slope of the secant line is [f(-4) - f(2)] / (-4 - 2) = [ -66 - 6]/(-4 - 2)

= (-72)/(-6) = 12

B = y - mx = 6 - (12)(2) = 6 - 24 = -18

y = 12x - 18

Note that 12(-4)-18 = -48-18 = -66 as it should