# How do you write the standard form of a line given (–1, 4) with a slope of –1?

May 31, 2016

$x + y - 3 = 0$

#### Explanation:

Standard form for the equation of a line is

$a x + b y + c = 0$

We begin by using the point slope form of the line

$\left(y - {y}_{1}\right) = m \left(x - {x}_{1}\right)$

$y - 4 = - 1 \left(x - \left(- 1\right)\right)$

$y - 4 = - x - 1$

$x + y - 4 = \cancel{- x} \cancel{+ x} - 1$

$x + y - 4 + 1 = \cancel{- 1} \cancel{+ 1}$

$x + y - 3 = 0$