Answer
$(2r-4t^2)(4r^2+8rt^2+16t^4)$
Work Step by Step
RECALL:
$A^3-B^3=(A+B)(A^2+AB+B^2)$
The given binomial can be written as:
$=2^3r^3-4^3(t^2)^3
\\=(2r)^3-(4t^2)^3$
The binomial above is a difference of two cubes.
Factor using the the formula above with $A=2r$ and $B=4t^2$ to obtain:
$=(2r-4t^2)[(2r)^2+(2r)(4t^2) +(4t^2)^2]
\\=(2r-4t^2)(4r^2+8rt^2+16t^4)$
