Question

1. find the centroid of a triangle mid points of whose sides are ( 1 , 2, -3 ) ( 3, 0, 1) and ( -1, 1, -4 )

2. find the coefficient of x5 y7 in ( x - 7y)12

3. the 3rd 4th and 5thterms in the expansion of ( x + a)n are respectivle 84 ,280 ,and 560 find the values of x ,a ,and n

Answer 1

1. (1,1,-2)and 2. 19, 958,400