Answer:
[tex]a=\frac{7}{3}[/tex]
Step-by-step explanation:
[tex]\frac{a-1}{a-3}=\frac{a+1}{a-4}[/tex]
[tex](a-1)(a-4)=(a-3)(a+1)[/tex]
[tex]a^2-5a+4=a^2-2a-3[/tex]
[tex]-5a+4=-2a-3[/tex]
[tex]-3a+4=-3[/tex]
[tex]-3a=-7[/tex]