Determine whether the function is linear or quadratic. Identify the quadratic, linear, and constant terms. linear function linear term: −18x2 constant term: –20 linear function linear term: 39x constant term: –20 quadratic function quadratic term: −18x2 linear term: 39x constant term: –20 quadratic function quadratic term: −12x2 linear term: −42x constant term: –20