Please help me on this question.

Lassify the function as linear or quadratic and identify the quadratic, linear, and constant terms. f(x) = (3x + 2)(−6x − 3) linear function; linear term: −21x; constant term: −6 linear function; linear term: −18x2; constant term: −6 quadratic function; quadratic term: 6x2; linear term: 24x; constant term: −6 quadratic function; quadratic term: −18x2; linear term: −21x; constant term: −6

Strawberries cause two hours per pound kate buys 5 pounds he gets 20% off discount on the total cost how much does kate pay for the strawberries

What is the missing step in this proof ?