Question

What is equation of a line with slope of 3 that goes through the point of (7,-1)

Answer 1

3x - y = 22

Explanation:

`P=(7,\,-1)\quad\implies\quad x_p=7\,,\quad y_p=-1`

y = mx + b

m = 3 ⇒ y = 3x + b

The line goes through P so:
`y_p=3x_p+b`

-1 = 3(7) + b

-1 = 21 + b

b = -22

y = 3x - 22

3x - y = 22

Answer 2

y = 3x - 22

Explanation:

y = mx + b

plug in slope

y = (3)x + b

plug in (x, y)

-1 = 3(7) + b

multiply

-1 = 21 + b

subtract

-22 = b

plug in b

y = 3x - 22