## College Algebra (6th Edition)

The binomial expression can always be rewritten as the following. $(A+B)^n = \sum _{k=0}^n C(n,r)* A^{n-r} * B^{r}$ Since we are finding the first 3 terms, we simply plug in the set $[0,1,2]$ $T_1 =C(9,0)*x^{9} =x^{9}$ $T_2 = C(9,1)*x^8*(-2y)=-18x^8y$ $T_3 =C(9,2)*x^7*4y^2= 144x^7y^2$