00:01
Okay, so we're asked to find a partial fraction decomposition.
00:04
If you look at our denominator and see that it can factor more, this is a linear factor, so this is okay.
00:12
This term factor into 2x minus 3 times x plus 3.
00:19
You can check this using the quadratic formula.
00:23
And that just turns into, let's see, all our linear factors are distinct.
00:29
So we have a case one.
00:31
So we get a over 2 .0.
00:34
X and that's right start with x plus plus b over 2x minus 3 plus c over x plus 3 okay now we have to multiply by a common denominator which is x plus 2 times 2x minus 3 times x plus 3 and what do we get we get negative 3 x squared minus 3x plus 27 is equal to a times 2x minus 3 times x plus 3 plus b times x plus 2 times x plus 3 and plus c times x plus 2 times 2x minus 3 okay let's expand this we get a is multiplied by 2x squared plus 3 x squared plus 3 x minus 9 plus b which is x squared plus 5 x plus 6 plus c times 2 x squared plus x minus 6 okay now moving on to the next page let's rewrite this we had negative 3 x squared minus 3 x plus 27 and that was all equal to this but i'm going to rewrite this with our a b and c so let's do that.
02:09
We get 2a x squared plus 3a x minus 9a plus bx squared plus 5b x plus 6b plus c up 2 cx squared plus cx minus 6c.
02:32
And now we need to combine our light term.
02:35
So we have x squared x squared x squared x squared x squared x x squared x x and last our constants and let's rewrite that as a system equations or constant here it's negative 3 negative 3 27 okay so we got 2a plus 3 oh that's a sorry about that so i'm going to read it like it like this 2a plus b plus 2c is equal to negative 3 3 plus 3a plus 5 b plus c is equal to negative 3, negative 9, a plus 6b, minus 6c is equal to 27.
03:36
Okay, so let me actually rewrite this equation by dividing it by 3.
03:44
We get negative to 3, a plus 2b, minus 2c is equal to 9.
03:53
Okay, and now i'm going to multiply this equation.
03:56
Or not, i'm just going to actually move this over here and eliminate my a.
04:04
So i get 3a plus 5b plus c is equal to negative 3...