Question

Write an equation in point-slope form of the line that passes through the given points, then write the equation in slope-intercept form.

(-9,7) (9,1)
What is the point-slope form of the equation of the line?

Answer 1

Equation of line is given as y = mx + c, where m is the slope and c is the y-intercept.

First find the slope.

Formula for slope is given as (y2-y1)÷(x2-x1) or (y1-y2)÷(x1-x2).

Slope = (7-1)÷(-9-9)

= -6/18

= -1/3

Equation of line is y = -1/3 + c.

Substitute either one of the points into the equation to find c.

1 = -1/3(9) + c

c = 4

Hence equation of line is y = -1/3x + 4