Question

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

Answer 1

Answer:

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

Step-by-step explanation:

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

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

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

=(x^2-4x+2^2)-25+10y-y^2

=(x^2-4x+2^2)-(25-10y+y^2)

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

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

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