Question

What is the y intercept of a line that passes through (1,-7) and (5,-25). How do I find it.

Answer 1

Answer:

y- intercept = - 2.5

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 m using the slope formula

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

with (x₁, y₁ ) = (1, - 7) and (x₂, y₂ ) = (5, - 25)

m = $\frac{-25+7}{5-1}$ = $\frac{-18}{4}$ = - 4.5 , then

y = - 4.5x + c

To find c substitute either of the 2 points into the equation

Using (1, - 7), then

- 7 = - 4.5 + c ⇒ c = - 7 + 4.5 = - 2.5

y- intercept c = - 2.5