we need to clear y in order to find the expression in terms of x
[tex]\begin{gathered} 2y=0.4x-4x-3 \\ y=\frac{1}{2}(0.4x-4x-3) \\ y=\frac{1}{2}(-3.5x-3) \end{gathered}[/tex]evaluating in x=-1
[tex]\begin{gathered} y=\frac{1}{2}(-3.5(-1)-3) \\ y=\frac{1}{2}(3.5-3) \\ y=\frac{1}{2}(0.5) \\ y=\frac{1}{4} \end{gathered}[/tex]