Independent Variable: In this case, t is considered an independent variable since it represents Liam's age and can take on different values.
Dependent Variable: The dependent variable in this case is w(t), which depends on the values of the independent variable t. It represents Liam's weight and changes as his age increases.
Quadratic Equation: The equation for w(t), w(t) = t^2/2 + 20, is a quadratic equation because it involves squaring the independent variable (t^2 term).