Question

A line passes through ( 2, -1) and (4,5)

Which answer is the equation of the line ?

A) -3x + y = -7
B) -3x + y = 17
C) -3x + 5y = 13
D) -3x + 5y = -13

Answer 1

A)
`-3x+y=-7`

Explanation:

Slope of the line:

`(5-(-1))/(4-2) =(6)/(2) =3`

`y=mx+b`

`y=3x+b`

Plug in x and y values of any of the points.

`5=3(4)+b`

`5=12+b`

`b=-7`

Equation of the line:

`y=3x-7`

Subtract 3x from both sides:

`y-3x=-7`

`-3x+y=-7`

A is correct.