Step-by-step explanation:
Note that the denominators in the expression are perfect squares:
[tex] {x}^{2} - 5xy + 6 {y}^{2} = (x - 2y)(x - 3y)[/tex]
[tex] {x}^{2} - 4xy + 3 {y}^{2} = (x - y)(x - 3y)[/tex]
[tex] {x}^{2} - 3xy + 2 {y}^{2} = (x - y)(x - 2y)[/tex]
We can then write the given expression as
[tex] \frac{1}{ {x}^{2} - 5xy + 6 {y}^{2} } + \frac{a}{{x}^{2} - 4xy + 3{y}^{2} } + \frac{1}{{x}^{2} - 3xy + 2{y}^{2}}[/tex]
[tex] \frac{1}{ {x}^{2} - 5xy + 6 {y}^{2} } + \frac{a}{{x}^{2} - 4xy + 3{y}^{2} } + \frac{1}{{x}^{2} - 3xy + 2{y}^{2}}[/tex]
[tex] = \frac{1}{(x - 2y)(x - 3y)} + \frac{a}{(x - y)(x - 3y)} + \frac{1}{(x - y)(x - 2y)}[/tex]
[tex] = \frac{(x - y)(x - 2y) {(x -3y)}^{2} + a {(x - y)}^{2} (x - 2y)(x - 3y) + (x - y){(x - 2y)}^{2}(x - 3y) }{ {(x - y)}^{2} {(x - 2y)}^{2} {(x - 3y)}^{2} } [/tex]
