Setting linear coefficient of the Riccati equation to one

Question

Consider a Ricatti equation $u'=au^2+bu=0$. i.e. Riccati equation without free term and constant coefficients $a$, $b$.. Is it possible to make a linear transformation such that $b$ becomes 1? I want to find a linear transformation such that above equation becomes $u'=au^2+u$. So far, I have that it can't be done using linear transformations.