Question

What is the equation of line l?
y = -x - 1
y = x + 1
y = 3x - 3
y = -3x - 3

Answer 1

To find the equation of this line, let's first find the y-intercept of the line which is the point where the line crosses the y-axis.

To find the y-intercept, we start at the origin.

We go 0 units to the left or right and 3 units down.

So that's (0, -3).

Now we can confirm that the y-intercept is -3.

So for any of the equations that have a y-intercept that's not -3, we can immediately eliminate them.

So we can eliminate y = -x - 1 and y = x + 1.

Now we have two equations left, y = 3x - 3 and y = -3x - 3.

Now we have to look at our line.

Remember that positive slopes go up and negative slopes go down so we can confirm that the equation won't have a slope of -3.

So therefore, the equation is y = 3x - 3.

Answer 2

y = 3x-3

Explanation:

The line has a y intercept of -3 (where it crosses the y axis)

We know the slope is positive since it goes up from left to right

The only answer with a positive slope and a y intercept of -3 i

y = 3x-3