Answer:
C.
Step-by-step explanation:
Hi there!
To answer this, we must set it up as

Now we just use the distributive property to solve.
this becomes 
I hope this helps!
for a triangular prism, its volume will simply be <u>area of its base</u> times its length.
the are of the base for this one is simply any of those triangular bases. Now, let's notice, the right-triangle has a base of 9 and a height o 9, notice the tickmarks, whilst the prism also has a length of 13.

<span><span><span><span><span>6x</span>y</span>−<span><span>2x</span>y</span></span>−<span><span>x2</span><span>y2</span></span></span>+<span><span>10x</span>y</span></span><span>=<span><span><span><span><span><span><span>6x</span>y</span>+</span>−<span><span>2x</span>y</span></span>+</span>−<span><span>x2</span><span>y2</span></span></span>+<span><span>10x</span>y</span></span></span><span>=<span><span><span><span><span>6x</span>y</span>+<span>−<span><span>2x</span>y</span></span></span>+<span>−<span><span>x2</span><span>y2</span></span></span></span>+<span><span>10x</span>y</span></span></span><span>=<span><span>(<span>−<span><span>x2</span><span>y2</span></span></span>)</span>+<span>(<span><span><span><span>6x</span>y</span>+<span>−<span><span>2x</span>y</span></span></span>+<span><span>10x</span>y</span></span>)</span></span></span><span>=<span><span>−<span><span>x2</span><span>y2</span></span></span>+<span><span>14x</span>y
</span></span></span>=−x2y2+14xy