Question

find the zero of quadric polynomial ax2+(a+b) x+b

Answer 1

ax2+(a+b)x+b
=ax2+ax+bx+b
=ax(x+1)+b(x+1)
=(ax+b)(x+1)
ax+B=0
x=-b\a
x+1=0
x=-1
so the two zeroes are -b/a and -1