Question

(y-4) - (4-y)(4+y)

Answer 1

(y-4) - (4-y)(4+y) =(y-4) +(-4+y)(4+y) =(y-4)(1+4+y)=(y-4)(5+y)

Answer 2

(y-4) - (4-y)(4+y) =(y-4) +(y-4)(y+4) =(y-4)(1+y+4)=(y-4)(y+5)