Ok, first you need to know the equation of a line: y = mx + b where m is the slope of the line and b is the single point on the line that touches the y axis.
Let's find m first using the equation for slope. It is the rise of the line which is the difference of the two y coordinates of the points divided by the difference of the two x coordinates of the points (-4,1) and (2,1):
m = (y₂ - y₁)/(x₂ - x₁)
m = (1 - 1)/(-4 - 2)
m = 0/-6
m = 0
This means the lie is going to be completely horizontal since it has no slope.
Now to find b, we have to find the entire equation of the line through a method called "point-slope form" of a line:
y - y₁ = m(x - x₁)
You simply plug a given point into this equation (x₁, y₁) and the slope m, and the equation in the end will look like the standard form y = mx + b:
y - 1 = 0(x - 2)
y -1 = 0
y = 1
This line would go through the y axis at the point (0, 1) and continue onward forever in both directions horizontally.
