X 1, x2, …, xk(k≤4) will be taken as the abscissa of the intersection of Y = X 4 and y=4-ax images.

Y=x4 is similar to Y = x 2, so there are only two real roots x 1x2.

For the function y=4/x

When 0

When x is 2 to positive infinity and -2.

Y=4 axis passes through (0,4)

X 1x2 is positive and negative.

Draw y = x 4 and x =+2, and x =-2 corresponding to points A, B and (0,4) C.

When y=4-ax passes through A and C, X 1 =-2, (X 1, 4/X 1) is on the straight line Y = X, which is not satisfied.

Turn a nearly straight line clockwise around c, x=0. This process satisfies the meaning of the question, and A is negative infinity to -6 (open interval).

Similarly, a can also be 6 to positive infinity.

To sum up, A is negative infinity to -6 (open interval), and up (open interval) 6 is positive infinity.