Solucionar I*xgtc*f*x+a-b

$$I \cdot x \gt c \cdot f \cdot x + a - b$$

Resolver para x

$$\left\{\begin{matrix}x>-\frac{b-a}{I-cf}\text{, }&I>cf\\x\in \mathrm{R}\text{, }&a<b\text{ and }I=cf\\x<-\frac{b-a}{I-cf}\text{, }&I<cf\end{matrix}\right.$$

Resolver para f

$$\left\{\begin{matrix}f>\frac{Ix+b-a}{cx}\text{, }&\left(c>0\text{ and }x<0\right)\text{ or }\left(x>0\text{ and }c<0\right)\\f\in \mathrm{R}\text{, }&\left(a<Ix+b\text{ and }c=0\right)\text{ or }\left(a<b\text{ and }x=0\right)\\f<\frac{Ix+b-a}{cx}\text{, }&\left(c<0\text{ and }x<0\right)\text{ or }\left(c>0\text{ and }x>0\right)\end{matrix}\right.$$