Question 172382
k=0 ----> y^2+8y = y(y+8)



k=7 ----> y^2+8y+7 = (y+7)(y+1)



k=12 ----> y^2+8y+12 = (y+6)(y+2)



k=15 ----> y^2+8y+15 = (y+5)(y+3)



k=16 ----> y^2+8y+16 = (y+4)(y+4)