00:01
Okay, with this quadratic, it's in standard form.
00:06
So this is a, this is b, this is c.
00:11
I like to just write it this way.
00:17
So we're going to start with the axis of symmetry.
00:23
So that is going to be x equals the opposite of b over 2a.
00:29
So i'm going to do my work over here.
00:34
So the opposite of b would be negative 10.
00:39
2a would be 2 times 2 or negative 10 fourths, which simplifies to negative 5 halves.
00:49
So x equals negative 5 halves, or if you prefer, x equals negative 2 .5.
01:08
Okay, now i'm going to do the vertex.
01:10
And i started with the axis of symmetry because that negative 2 .5 is what goes right there.
01:18
It's the x coordinate of the vertex.
01:23
But to do the math, i'm actually going to use the fraction because i'm going to try to do this without a calculator.
01:30
So 2 times negative 5 halves squared plus 10 times negative 5 halves.
01:41
Now, if you're allowed to use a calculator, then by all means, just use the decimal.
01:47
So negative 5 halves squared is 25 fourths.
01:52
You got to make sure you square the bottom and the top.
01:55
Plus 10 times negative 5 halves.
02:04
So this becomes 50 fourths or 25 halves.
02:10
This becomes negative 50 halves or, well, actually, we'll leave it like that.
02:23
And 7 is 14 halves.
02:27
So i changed everything to a denominator of 2.
02:30
So i get negative 25 halves minus 14 halves.
02:39
That is negative 39 halves.
02:48
Now, as a decimal, that is negative 19 .5.
02:58
And the directions did say you could use decimals.
03:02
All right, the y -intercept.
03:03
That's the easiest one because the y -intercept, if i'm in standard form, is just equal to that c value...