Question

减去2-3x等于6x平方-3x-8的代数式是?

Answer 1

x-y=3

xy=-4

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

x^2+8+y^2=9

x^2+y^2=1

x^2+xy+y^2=1-4=-3

x^2-3xy+y^2=1+3*4=13