The equation \( y = 9x^2 \) is not a linear relationship.
In a linear relationship, the equation can be expressed in the form \( y = mx + b \), where \( m \) represents the slope and \( b \) is the y-intercept. The equation \( y = 9x^2 \) represents a quadratic relationship, as it contains the term \( x^2 \). This means that the graph of the equation will be a parabola, not a straight line.