Answer:
373248cm³
Explanation:
first we need to find the value of the side length by plugging in the value of y and x 
side length = 8x²y + y³
x = 1/2 and y = 4 ( plug in these values ) 
side length = 8(1/2)²4 + (4)³
we can evaluate using pemdas
p - parenthesis 
e - exponents
md - multiplication and division ( left to right ) 
as - addition and subtraction ( left to right ) 
first we evaluate anything in the parenthesis if needed. its not needed though because there is no operations in the parenthesis 
Then we evaluate exponents 
side length = 8(1/2)²4 + (4)³
there are 2 so we evaluate them 
(1/2)² = 1/4 and 4³ = 64
side length = 8(1/4)4 + 64
next we do the multiplication and division going left to right
8 * 1/4 = 2 
(2)(4) + 64
2 * 4 = 8 
side length = 8 + 64
finally the addition 
side length = 72
No we want to find the volume of the cube
We can find the volume of a cube by simply cubing the side length 
The cube has a side length of 72cm 
so the volume is equal to 72³ = 373248cm³