y' = 2x = mtan
y + 3 = 2x(x + 1)
y = 2x2 + 2x - 3. But this equation of the tangent line must also satisfy the original equation so ...
2x2 + 2x - 3 = x2 + 1
x2 + 2x - 4 = 0
by quad formula: x = (-2 ±√20)/2 = -1 ±√5
So y = (-1 + √5)(x +1) - 3. and y = (-1 - √5)(x +1) - 3