30 points i’m stuck on this problem : complete the square 2t^2-4t-1 i know the answer i just don’t know how to get it

First, factor out the 2 from the first two terms:

To complete the square, we need to add and subtract a term to the grouped term so that it's the result you would get from squaring some binomial. In this case, notice that

which means we should add and subtract 1 as follows, then condense the quadratic terms:

the answer is a if my teacher taught me correct

to find the perimeter, you add up all the lengths of the sides. in this case you would have to add up 18+22+40+80 which equals 160.