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.

AB
Answered by Adam B. Further Mathematics tutor

5318 Views

See similar Further Mathematics GCSE tutors

Related Further Mathematics GCSE answers

All answers ▸

Simplify fully the expression ( 7x^2 + 14x ) / ( 2x + 4 )


Find the coordinates of the minimum/maximum of the curve: Y = 8X - 2X^2 - 9, and determine whether it is a maximum or a minimum.


(x+4)((x^2) - kx - 5) is expanded and simplified. The coefficient of the x^2 term twice the coefficient of the x term. Work out the value of k.


A curve has equation: y = x^3 - 3x^2 + 5. Show that the curve has a minimum point when x = 2.


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences