Question

Answer 1

a: A+B+C

=-7x^2-4xy+2y^2+2x^2+xy-1/2y^2+x^2+4xy-y^2

=-4x^2+xy+1/2y^2

b: A-B-C

=A-(B+C)

=-7x^2-4xy+2y^2-(3x^2+5xy-3/2y^2)

=-7x^2-4xy+2y^2-3x^2-5xy+3/2y^2

=-10x^2-9xy+7/2y^2

c: A+B-C

=-7x^2-4xy+2y^2+2x^2+xy-1/2y^2-x^2-4xy+y^2

=-6x^2-7xy+5/2y^2

d: A-B+C

=-7x^2-4xy+2y^2-2x^2-xy+1/2y^2+x^2+4xy-y^2

=-8x^2-xy+3/2y^2