Question

What is the equation of the line, in slope-intercept form, that contains the points (-1,8) and (2,-1)?

Answer 1

Correct Answer: Option A

From the given points, we can find the slope(m):

$m= \frac{-1-8}{2-(-1)} =-3$

Thus the slope of the line containing the given two pints is -3.

Using slope, and a point we can write the equation as:

y - 8 = -3 ( x  + 1)
y - 8 = -3x -3 
y = -3x + 5

Answer 2

Y-yo = m (x-xo)
 We must find the slope of the line:
 m = (y2-y1) / (x2-x1)
 m = (- 1-8) / (2 - (- 1))
 m = (- 9) / (3)
 m = -3
 The ordered pair is:
 (xo, yo) = (- 1, 8)
 Substituting:
 y-8 = -3 (x + 1)
 Rewriting:
 y = -3x-3 + 8
 y = -3x + 5

 Answer:
 The equation of the line is:
 A) y = -3x +5