00:01
What is the partial fraction decomposition of the given rational expression? the first thing we need to do is factor this denominator.
00:08
So i'm going to pull out an x.
00:09
That'll be x squared plus 2x minus 3.
00:12
And now i'm going to factor this, and i'll get x plus 3 and x minus 1.
00:20
So i'm going to have the fraction 13, x plus 3 over x, x plus 3, over x plus 3, x plus 3, 1 and that equals some numerator over x plus some numerator over x plus 3 plus some another numerator over x minus 1 now we need to use this fact to break this down the first thing we want to do is look at this as an equation so i'm going to this all of this right here i'm going to look at as an equation and so i'm going to eliminate the fractions now by multiplying by my least common denominator x x plus 3 x minus 1 so i'm going to do that to each fraction so that's going to mean we're left with 13x plus 3 equals now here we go our x is to eliminate i have a x plus 3 x minus 1 plus b my x plus 3 is eliminate i'll have x x minus 1, and then my x minus 1 is eliminate, and i have c times x and x plus 3.
01:48
Now let's go ahead and get rid of all these parentheses.
01:51
So that's going to become, i know that this multiplies to be x squared plus 2x minus 3.
01:59
So i'm just going to distribute a to that parentheses.
02:03
So it's going to be a x squared plus 2x minus 3.
02:06
Plus 2a x minus 3a.
02:10
This will be plus bx squared minus bx plus cx squared plus 3cx.
02:23
Now we're going to group that's still 13x plus 3.
02:27
Now i'm going to group it according to our variables x.
02:31
So i've got my x squared.
02:33
So i'm going to have a x squared plus bx squared.
02:38
Plus cx squared.
02:40
Now i'm going to look at my x's.
02:43
So here we go ahead.
02:44
There's my x's.
02:45
I have plus 2 a x minus bx plus 3 cx.
02:51
And then finally i'm going to look at my one term that does not have a variable and that's negative 3a.
03:02
So i'm going to keep do this a little bit more.
03:05
I'm going to factor out my x squared so that be a plus b plus c.
03:10
Then i'll come over here and i'm going to factor out my x's.
03:13
That'll be 2a minus b plus plus 3c, excuse me.
03:22
And then i'm just going to have minus 3a...