77.1k views
4 votes
30 Points please help 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

User Endavid
by
7.3k points

1 Answer

5 votes

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


2t^2-4t-1=2(t^2-2t)-1

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


(t-1)^2=t^2-2t+1

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


2(t^2-2t+1-1)-1=2(t^2-2t+1)-3=2(t-1)^2-3

User Hanady
by
6.6k points
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