Find the Equation with a Point and Slope What is the equation of the line that passes through the point (-5,-3) and has a slope of -1 ?

What is the equation of the line that passes through the point $(- 5, - 3)$ and has a slope of $- 1$ ?

Step 1

Find the value of $b$ using the formula for the equation of a line.

Use the formula for the equation of a line to find $b$ .

$y = m x + b$

Substitute the value of $m$ into the equation.

$y = (- 1) \cdot x + b$

Substitute the value of $x$ into the equation.

$y = (- 1) \cdot (- 5) + b$

Substitute the value of $y$ into the equation.

$- 3 = (- 1) \cdot (- 5) + b$

Find the value of $b$ .

Rewrite the equation as $(- 1) \cdot (- 5) + b = - 3$ .

$(- 1) \cdot (- 5) + b = - 3$

Multiply $- 1$ by $- 5$ .

$5 + b = - 3$

Move all terms not containing $b$ to the right side of the equation.

Subtract $5$ from both sides of the equation.

$b = - 3 - 5$

Subtract $5$ from $- 3$ .

$b = - 8$

Step 2

Now that the values of $m$ (slope) and $b$ (y-intercept) are known, substitute them into $y = m x + b$ to find the equation of the line.

$y = - x - 8$

Step 3