Question

What is the equation of the line given that the slope is 2 and it is going through the point (6,

-8)?

Answer 1

2x - y - 20 = 0

Explanation:

`P=(6,\,-8)\quad\implies\quad x_p=6\,,\quad y_p=-8`

y = mx + b

m = 2 ⇒ y = 2x + b

The line goes through P so:
`y_p=2x_p+b`

-8 = 2(6) + b

-8 = 12 + b

b = -20

y = 2x - 20

2x - y - 20 = 0

Answer 2

y = 2x - 20

Explanation:

equation: y = mx + b

plug in slope

y = (2)x + b

plug in (x, y)

-8 = 2(6) + b

multiply

-8 = 12 + b

subtract

-20 = b

plug in b

y = 2x - 20