x=0.3

x=0.4

x=0

My solution:

**R1**=10k ohms

**R2**=100k ohms

**R3**= 1k ohms

**Rp**=10k ohms potentiometer

Vin=(-R2/R1)*V0

Vo=(R3+(xRp*R2/xRp+R2))/(xRp*R2/xRp+R2)

Vo/Vin= (-R2/R1)*(R3+(xRp*R2/xRp+R2))/(xRp*R2/xRp+R2)

When x= 0.3, Vo/Vin=-11.333

When x= 0.4, Vo/Vin=-11.25

When x= 0, Vo/Vin= -∞ (negative infinity)

I'm pretty happy with that, particularly for when x=0 gain tends to infinity which is what the equation proves, anyone back that up?