The coefficient of x in the expansion of (1−ax)−1(1−bx)−1(1−cx)−1 is?
If the coefficient of x7 in [ax2+(1bx)]11 equals the coefficient of x−7 in [ax2−(1bx)]11, then 'a' and 'b' satisfy the relation
In the expansion of ( ax+bx)12, the coefficient of x−10 will be