The coefficient of the x^3 term in the expansion of (3x + a)^4 is 216. Find the value of a.

From the binomial theorem we know that the x^3 term in the expansion of the above expression must satisfy,
4C3 * (3x)^3 * a = 216x^3.
Hence, after multiplying out we must have,
108a * x^3 = 216x^3
and therefore the value of a must be 2.

Related Further Mathematics GCSE answers

All answers ▸

If y=(x^2)*(x-10), work out dy/dx


How can a system of two linear equations be solved?


f'(x) = 3x^2 - 5cos(3x) + 90. Find f(x) and f''(x).


Why does tanx = sinx/cosx ?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences