00:01
So now we have a function.
00:02
Why equals two x to the third minus three x squared minus 12 ax plus 20.
00:13
And we want to find where this function has tangent lines that are parallel.
00:20
So we want tangent lines and we want them to be parallel to the x axis.
00:27
So if they're parallel to the x axis, that means we want them to have ah, slope or a derivative thio equal zero because we're basically gonna have if this is our x axis, we wanna have places.
00:41
If the function looked like this, we want the tangent line to be parallel to the x axis.
00:47
So we want a slope of zero.
00:49
So we need to find that derivative.
00:51
And then we want to know when the derivative is equal to zero.
00:57
So we have our power rules.
00:59
So we have six x squared minus six x minus 12 and then the derivative of 20th zero.
01:09
And so i'm gonna do a little bit of factoring here...