Solve for $y$: $4+2.3y = 1.7y - 20$
First we get all the terms with $y$ on one side by subtracting $1.7y$ from both sides.  This gives us $4+0.6y = -20$.  Subtracting 4 from both sides gives $0.6y = -24$.  Dividing both sides by 0.6 isolates $y$ and gives us $y = -24/(0.6) = -240/6 = \boxed{-40}$.