How can commutative and associative properties of addition you find the sum mentally?

Which values for a and b will create infinitely many solutions for this system of equations? ax-y=8 2x+y=b

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

Ijust need to see how to do this. so you don’t have to answer all of them just a step by step explanation of one.