Find the first three terms in ascending power of 'x' of the binomial expression of (3+bx)^5 where b is a non zero constant.

Answer 1

3^5 + ***** 3^4 (bx) + ****** 3^3 (bx)^2 + ........
now get binomial coefficients for fifth power from Pascal's triangle or formula

1 5 10 10 5 1
so
3^5 + 5*3^4 b x + 10 * 3^3 b^2 x^2

243 + 405 b x + 270 b^2 x^2 ......