If you can give me more information on this I could help you a bit more respond.
X × x = x^2
x × -3 = -3x
3 × x = 3x
3 × -3 = -9
x^2 + 3x - 3x - 9
So I would agree with C because the -3x and the 3x cancel each other out. I hope this helps!
Here is all I got for you. From the starting expression to the simplest one.
t^2 + 4tv + 4^2 =
t^2 + 4tv + 16 =
t(t + 4v) + 16
