No.
\(\displaystyle y^{2}(a-b)-(a-b)=(y^{2}-1)(a-b)\)
Now, finish the difference of two squares that remains.
To check oyur answer, FOIL it back out to see if you get the original problem. If not, there is something wrong.
If we FOIL \(\displaystyle (y+a+b)(-y+a+b)\), we get:
\(\displaystyle -y^{2}+a^{2}+2ab+b^{2}\)
See?. Nothing like the original.
