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