[tex]\qquad\qquad\huge\underline{{\sf Answer}}[/tex]
Let's evaluate ~
As the denominator of both the terms is same, we can simply perform subtraction on numerator.
That is :
[tex]\qquad \sf \dashrightarrow \: \dfrac{a - 2}{ {a}^{2} + 7a + 6 } - \dfrac{5a - 6}{ {a}^{2} + 7a + 6 } [/tex]
[tex]\qquad \sf \dashrightarrow \: \dfrac{a - 2 - (5a - 6)}{ {a}^{2} + 7a + 6 } [/tex]
[tex]\qquad \sf \dashrightarrow \: \dfrac{a - 2 - 5a + 6}{ {a}^{2} + 7a + 6 } [/tex]
[tex]\qquad \sf \dashrightarrow \: \dfrac{ - 4a + 4}{ {a}^{2} + 7a + 6 } [/tex]
