Term Definition
constant of proportionality the constant value of the ratio of two proportional quantities x and y; usually written y = kx, where k is the factor of proportionality
slope to have or take an inclined or oblique direction or angle considered with reference to a vertical or horizontal plane; slant.
direct variation mathematical relationship between two variables that can be expressed by an equation in which one variable is equal to a constant times the other
x-intercept the x-coordinate of a point where a line, curve, or surface intersects the x-axis
linear equation a first-order equation involving two variables: its graph is a straight line in the Cartesian coordinate system.
is a point where the graph of a function or relation intersects with the y-axis of the coordinate system.
point-slop from they give you a point (x1, y1) and a slope m, and have you plug it into this formula:

y – y1 = m(x – x1)

unit rate describes how many units of the first type of quantity corresponds to one unit of the second type of quantity.
slop-intercpt from goes straight up and down, its slope is undefined. Also, the x value of every point on a vertical line is the same
proportional relationship are the comparison of two equal ratios. Therefore, proportional relationships are relationships between two equal ratios.
rate of change The slope of a line is a rate of change.

intersecting lines Two lines that cross each other. Lines intersect at one point unless the lines fall directly on top of each other