Решите срочно (b-7)*(b+4)-(b+2)*(b+1)

(b-7)*(b+4)-(b+2)*(b+1)=b^2+4b-7b-28-(b^2+b+2b+2)=b^2+4b-7b-28-(b^2+3b+2)=b^2+4b-7b-28-b^2-3b-2= -6b-30