Find the zeros of the polynomial function. State whether the graph crosses the x-axis, or touches the x-axis and turns around, at each intercept. f(x) = x4 - 81x2

Question

A. x = 0, touches the x-axis and turns around;
x = 81, touches the x-axis and turns around
B. x = 0, crosses the x-axis;
x = 9, crosses the x-axis;
x = -9, crosses the x-axis
C. x = 0, touches the x-axis and turns around;
x = 81, crosses the x-axis
D. x = 0, touches the x-axis and turns around;
x = 9, crosses the x-axis;
x = -9, crosses the x-axis

Answer 1

Answer: D