This math topic focuses on identifying the line equations that are perpendicular to given line equations. It includes converting the line equations from standard form to slope-intercept form to ascertain the slope, and then determining the perpendicular slopes accordingly. Each question presents a line equation in standard form, and students must select the line equation among the provided choices that has a slope perpendicular to the given equation. This involves understanding and applying the concept that the slope of perpendicular lines are negative reciprocals of each other.