Question

Factorise y²-16y-105​

Answer 1

Answer:

Step-by-step explanation:

This is the answer.

Answer 2

Answer:

(x+5)(x-21)

Step-by-step explanation:

i will explain in terms of: ax²+bx+c

if a=1, this will work all the time.

two factors of c will equal two numbers that add up to b.

5 and -21 will work b/c:

5+(-21) is the same thing as 5-21 which equals -16, the value of b

5×-21 also equals -105