What is the coefficient of x3 in (2x-4)(x+6)2 ?
2
3
4
5
We use the identity (a+b)2 = a2 + b2 + 2ab to expand the second term.
(2x-4)(x+6)2 = (2x-4)(x2+36+12x)
= 2x3+72x+24x2−4x2+32−48x
= 2x3+72x+20x2+32−48x
The coefficient of x3 in (2x-4)(x+6)2 is 2
What is the coefficient of x in x3 + 3x2 – 2x - 1