Take a group of data with an average of x 1, x 2 Xn, xn are expanded a times to ax1, AX2 Axn, then the average of these new numbers is? Can you explain why

Take a group of data with an average of x 1, x 2 Xn, xn are expanded a times to ax1, AX2 Axn, then the average of these new numbers is? Can you explain why

ax
Average = (x1 + x2 +xn）/n=x
Expanded = (ax1 + AX2 +axn)/n=a（x1+x2…… +xn）/n=ax

In the plane rectangular coordinate system, O is the coordinate origin and a (COSA, 0), B (0, Sina) if the point m (x, y) satisfies the vector om = vector 3om-4ob, when a changes, the point

The question should be: what is the trajectory of M?
So the answer is: ellipse
M(3cosa,-4sina)
According to the elliptic equation x ^ 2 / 9 + y ^ 2 / 16 = 1