Question

What is an equation of the line that passes through the points (-1, 6) and (-1,-5)?

Answer 1

Answer:

x = -1    

Step-by-step explanation:

1) First, find the slope of the line by using the slope formula, $m = \frac{y_2-y_1}{x_2-x_1}$. Substitute the x and y values of the given points into the formula and solve:

$m = \frac{(-5)-(6)}{(-1)-(-1)} \\m = \frac{-5-6}{-1+1}\\m =\frac{-11}{0}$

The result we got was $-\frac{11}{0}$, but we can't divide by zero. This means that the slope of the line must be undefined instead.

2) All vertical lines have a slope that is undefined. So, this line must be vertical.

All vertical lines are represented by the equation x = a single number. That number represents the x-value of all the points the vertical line intersects. So, take the x-value of the given points (in this case, -1) and put it into that equation. So, the equation of the line must be x = -1.