1. I would call quadrants i, ii, iii, iv as a, b, c, d
2.Which type of variables are usually on the y-axis and represent output?
they usually are the dependent variables, that is, they depend on the x value, such as velocity, price, income.
3.Which type of variables are usually on the x-axis and represent input?
those are the independent variables such as time, distance, price.
4.Which type of slope is represented on a graph as a horizontal line?
the slope of an horizontal line is zero.
5.Find the slope of 2x + 4y = 12
the general form of the line is:
4y = - 2x + 12
y = -(1/2)x + 3
hence the slope is -1/2