Question

help please! Darren is finding the equation in the form y = m x + 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? a) –34 b) –19 c) 2 d) 14

Answer 1

Answer: d) 14

Explanation:

Equation of a line passing through (a,b) and (c,d):

`(y-b)=(d-b)/(c-a)(x-a)`

Equation of a line passing through (2, 18) and (–3, 8):

`(y-18)=(8-18)/(-3-2)(x-2)\\\\\Rightarrow\ (y-18)=(-10)/(-5)(x-2)\\\\\Rightarrow\ (y-18)=2(x-2)\\\\\Rightarrow\ y-18=2x-4\\\\\Rightarrow\ y=2x-4+18\\\\\Rightarrow\ y=2x+14`

Comparing resulting equation
`y=2x+14` to
`y = m x + b`, we get value of b= 14.

Hence, correct option is d) 14