Question

Which equation best represents the line graphed above
x=-1
x=1
y=-1
y=x-1

Answer 1

That's a vertical line, and vertical lines have a very specific form. Since every point on the line has the same x-coordinate, the equation does NOT depend on y, but only on the value of x that is the same for each point. Hence, the equation for a vertical line is always of the form:

x=a

for some constant a.

Answer 2

So, which is it?

Answer 3

would it be the second one?

Answer 4

Here's an example of a vertical and a horizontal line (for a horizontal line, the equation depends only on y; for vertical, only on x)

Answer 5

The 2nd one says "x=1" so that is a vertical line where every point has x=1. You are right that it is a vertical line equation, but is it THIS vertical line equation?

Does THIS line have every x-coordinate = 1?

Answer 6

would it be the last option? i suck at this

Answer 7

The last one involves both x and y, so that is not an equation for a vertical line.

Again, a vertical line is ALWAYS of the form:

x = a

for some constant a. It does not involve the y variable. The equation depends ONLY on the constant value of x, the x-coordinate through which EVERY point passes.

What value of x is the x-coordinate for EVERY point on your line?