Meritnation experts i am unable to understand help me Share with your friends Share 0 Shilpa Patel answered this Dear student let f(x)= x^2+x+a As x+3 is factor then x+3=0 x=-3 Now f(-3) = (-3)^2 -3 +a =0 9 - 3 + a=0 6+a=0 a=-6 regards. 0 View Full Answer