ANSWER:
y ≈ (-10/19)*(2.8 - 3) + 1 = 1 2/19 ≈ 1.105
Explanation:
y = (2x+13)/(2x^2+1) 
 
y' = ((2x^2+1)*(2) - (2x+13)(4x)) / (2x^2+1)^2 
 
at x=3, this is 
 
y'(3) = (19*2 - 19*12)/19^2 = -10/19 
 
So, your linearization is 
 
y ≈ (-10/19)*(x-3) + 1 
 
At x=2.8, this is 
 
y ≈ (-10/19)*(2.8 - 3) + 1 = 1 2/19 ≈ 1.105