Model Direct Variation
The Equation of Direct Variation y = ax - y varies directly with x Constant of Variation - a is called the constant of variation. (Basically, a is slope) - a cannot be 0.
Important: For a relation to be considered a direct variation, The Relation: - Must be linear - Must pass through the origin (O, O) (no intercept)
Graph the equation. y = 3x
Graph the equation. y = -4x
Graph the equation. y = 2x + 1
Write and graph a direct variation equation that has the given ordered pair as a solution. (3, -9)
Write and graph a direct variation equation that has the given ordered pair as a solution. (-7, 4)
Write and graph a direct variation equation that has the given ordered pair as a solution. (5, 3)
Write and graph a direct variation equation that has the given ordered pair as a solution. (6, -2)
The variables x and y vary directly The variables x and y vary directly. Write an equation that relates x and y. Then find y when x = 12. x = 1, y = 2
The variables x and y vary directly The variables x and y vary directly. Write an equation that relates x and y. Then find y when x = 12. x = -2, y = 5
The variables x and y vary directly The variables x and y vary directly. Write an equation that relates x and y. Then find y when x = 12. x = 3, y = -2
The variables x and y vary directly The variables x and y vary directly. Write an equation that relates x and y. Then find x when y = -4. x = 1, y = 2
The variables x and y vary directly The variables x and y vary directly. Write an equation that relates x and y. Then find x when y = -4. x = -2, y = 5
Tell whether the equation represents direct variation Tell whether the equation represents direct variation. If so, give the constant of variation. y = 2x – 1 y = 3x 2x + y = 0 y -1 = 2x 3y = 4x 3y -1 = x