00:01
I want to solve the equation 2x squared minus 4 x minus 1 equals 0 by completing the square.
00:07
Since our leading coefficient is not 1, let's make it 1 by dividing everything by 2.
00:12
Then we have x squared minus 2x minus 1ā2 .1ā2.
00:17
Now we'll make a little space to complete the square by adding 1ā2 to both sides.
00:23
And we're going to come up with a constant we can add to both sides of the equation to stay balanced so that we can write the left -hand side as a perfect square.
00:32
That's called completing the square.
00:34
To find that number, we take the coefficient on x, take half of it, which would be negative 1, and square it which would be 1.
00:42
So the left hand side can be written as x minus 1 squared.
00:47
1 1 1, if we think of 1 as 2 halves, is 3 halves...