let m and b be real numbers and let the function f be defined by

$\displaystyle f(x)=\begin{cases}

& \text{ if } x= 1+3bx+2x^2 (x\leq 1) \\

& \text{ if } x= mx+b (x greater than 1)

\end{cases}$

If f is both continuous and differentiable at x=1, then

m=?

b=?

my steps

-substitute for x=1

$\displaystyle 1+3b(1)+2(1)^2=m(1)+b$

-combine like terms

$\displaystyle 3+3b=m+b$

-rearrange for m

$\displaystyle m=3+2b$

-substitute back in

3+3b=(3+2b)+b

3+3b=3+3b

-this is where i am lost i dont even have a variable when I solve...

what did I do wrong?

All help is appreciated.