Question

factorise x^2-y^2-2x+6y-8

Answer 1

x^2 - y^2 - 2x + 6y - 8 
= (x^2 - 2x + 1) - (y^2 - 6y + 9) - 8 - 1 + 9 
= (x - 1)^2 - (y - 3)^2 
= [(x - 1) - (y - 3) ] [(x - 1) + (y - 3)] 
= (x - 1 - y + 3) ( x - 1 + y - 3) 
= (x - y + 2) (x + y - 4)