Question

A line passes through the points (
–
1,
–
9) and (1,7). Write its equation in slope-intercept form.
Write your answer using integers, proper fractions, and improper fractions in simplest form.

Answer 1

Answer:

y = 8x - 1

Step-by-step explanation:

the equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y- intercept )

calculate the slope m , using the slope formula

m = $\frac{y_{1}-y_{1} }{x_{2}-x_{1} }$

let (x₁, y₁ ) = (- 1, - 9 ) and (x₂, y₂ ) = (1, 7 )

substitute these values into the formula for m

m = $\frac{7-(-9)}{1-(-1)}$ = $\frac{7+9}{1+1}$ = $\frac{16}{2}$ = 8 , then

y = 8x + c ← is the partial equation

to find c, substitute either of the 2 points into the partial equation

using (1, 7 ) for x and y in the partial equation

7 = 8(1) + c = 8 + c ( subtract 8 from both sides )

- 1 = c

y = 8x - 1 ← equation of line