Answer
The identity is verified.
$sec^6x(sec~x~tan~x)-sec^4x(sec~x~tan~x)=sec^5x~tan^3x$
Work Step by Step
$sec^6x(sec~x~tan~x)-sec^4x(sec~x~tan~x)=sec^2x~sec^4x(sec~x~tan~x)-sec^4x(sec~x~tan~x)=(sec^2x-1)sec^4x(sec~x~tan~x)=tan^2x~sec^5x~tan~x=sec^5x~tan^3x$