[tex]y=mx+b\\\\A(0;\ 8);\ B(4;\ 3)\\\\substitution\\\\ \left\{\begin{array}{ccc}0m+b=8\\4m+b=3\end{array}\right\\\\\left\{\begin{array}{ccc}b=8\\4m+b=3\end{array}\right\\\left\{\begin{array}{ccc}b=8\\4m+8=3\end{array}\right\\\left\{\begin{array}{ccc}b=8\\4m=3-8\end{array}\right\\\left\{\begin{array}{ccc}b=8\\4m=-5&/:4\end{array}\right\left\{\begin{array}{ccc}b=8\\m=-\frac{5}{4}\end{array}\right[/tex]
[tex]Answer:y=-\frac{5}{4}x+8[/tex]
