im sorry for posting so many questions. this is the last.

"the line is a tangent to the parabola at the point (1,2). find a and b"

now i have no idea where to start here. i could assume solving simultaneuosly could give some sort of answer but it would contain both unknowns.

if i differentiate i get

and from the tangent we know that

at (1,2)

its here that im confused. whether the whole previous section is wrong i just cant get an answer.