Answer:
(y-3)(y+3)
Explanation:
This is a difference of squares.
Difference of squares is when you have a perfect square - another perfect square. You would square root both of them and add one and subtract one.
Solving it without difference of square.
y²+3y-3y-9 is the expanded form and from here you can factor.
You split the equation into two parts.
y²+3y and -3y-9
Factor out any common units.
y(y+3) -3(y+3)
You then put the units outside of parentheses together and the ones inside parentheses together. (The ones inside parentheses should both be the same.
This simplifies to (y-3)(y+3)