Question

the coefficient of x square in the expansion of (x+4) whole cube is​

Answer 1

Answer:

12

Step-by-step explanation:

By using binomial theorem:

(a+b)^3 = a^3 + 3a^2×b + 3a×b^2 + b^3

ie. (x+4)^3 = x^3 + 12x^2 + 48x + 64

Here coefficient of x^2 is 12

OR

T(r+1) = nCr × a^(n-r) × b^r

= 3Cr × x^(3-r) × 4^r

By looking at equation:

r = 1 (then only power of x becomes 2 ie. x^2)

=> 3C2 × x^2 ×4

= 3×4x^2

ie. coefficient is;

3×4

= 12