Question

Answer 1

a: (x+y+z)^2

=x^2+y^2+z^2+2xy+2yz+2xz

b: (a-b-c)^2

=a^2+b^2+c^2+2bc-2ab-2ac

c: (xy-3)^2

=x^2y^2-6xy+9

d: 2(1/2x^2+y)(x^2-2y)

=(x^2+2y)(x^2-2y)

=x^4-4y^2