A line equation is a mathematical representation of a straight line on a graph. The most common form is the slope-intercept form, written as y = mx + b, where m represents the slope of the line, and b is the y-intercept, the point where the line crosses the y-axis. This equation helps in understanding how changes in x affect y. Another form of the line equation is the point-slope form, expressed as y - y₁ = m(x - x₁). Here, m is the slope, and x₁ and y₁ are the coordinates of a specific point on the line. Both forms are useful for graphing and analyzing linear relationships in various fields, including physics and economics.