College Algebra 7th Edition

$(y+3)^{2}$
Rearrange the terms of the trinomial. $9+6y+y^{2}=y^{2}+6y+9$ Use the formula $a^{2}\pm2ab+b^2=(a\pm b)^{2}$ to factor the perfect square. $y^{2}+6y+9=(y+3)^{2}$