Step-by-step explanation:
Derivative of the first function:
![f(x)=2x^{4} -36x^{2} +2 on D:[-4,4]](https://tex.z-dn.net/?f=f%28x%29%3D2x%5E%7B4%7D%20-36x%5E%7B2%7D%20%2B2%20%20on%20D%3A%5B-4%2C4%5D)

set that equal to 0 and solve for possible x values.

put x back in to original equation to get a y value
y = 2, -160, -160,
Absolute min at (-3, -160) and (3, 160) and an absolute max at (0,2)
Second Part
Find derivative of 

set equal to zero, it is a quadratic so you can use the quadratic formula to solve for x
x= -5 or -5/3
put x back into the original function to get a y value
y = 1 or -973/27
so absolute max at (-5, 1) and absolute min at (-5/3, -973/27)