Can you please check my work and answers.
Find the x-intercepts of the polynomial function. State whether the graph crosses the x-axis, or touches the x-axis and turns around, at each intercept.
1.f(x) = (x + 1)(x - 3)(x - 1)^2
-I got -1 crosses the x-axis, 3 crosses the x-axis, 1 touches the x-axis and turns around
5.f(x) = x^4 - 16x^2
- I got x^2(x^2-16)
(x+4)(x-4)
0 touches the x-axis and turns around; 4 crosses the x-axis; -4 crosses the x-axis
7.x^4 + 5x^3 - 84x^2 = 0
I got 0 touches the x-axis and turns around;-12 crosses the x-axis; 7 crosses the x-axis