Question

Complete the equation of the line through 2,1 and 5,-8

Answer 1

Explanation:

Hello : let A(2,1) B(5,-8)

the slope is : (YB - YA)/(XB -XA)

(-8-1)/(5-2) = -9/3=-3

an equation is : y=ax+b a is a slope

y = -3x +b

the line through point (2,1) : 1= -(3)(2)+b

b = 7

the equation is : y =-3x+7

Answer 2

y - 1 = -3(x - 2)

Explanation:

As we move from the point (2, 1) to the point (5, -8), x (the run) increases by 3 and y (the rise) decreases by 9. Thus, the slope of this line is

m = rise / run = -9/3, or m = -3.

Then the equation of the line (in point-slope form) is

y - 1 = -3(x - 2)