Question

Factorise
Please factorise it and send me the pictures!
x²-4x-21+10y-y²

Answer 1

Answer:

Step-by-step explanation:

x^2-4x-21+10y-y^2

=x^2-4x+2^2-2^2-21+10-y^2

=(x-2)^2-{4+24-10+y^2}

=(x-2)^2-(y-5)^2

=(x-2+y-5)(x-2-y+5)

=(x+y-7)(x-y+3)