Find the maximum value of \( Z = 4x + y \) under the given constraints by graphical method:
\[
x + y \leq 50, \quad 3x + y \leq 90, \quad x \geq 0, \quad y \geq 0.
\]
Show Hint
To maximize a function under constraints, use the graphical method by plotting constraints and evaluating the objective function at corner points.
We solve the system graphically by plotting the lines:
\[
x + y = 50 \quad \text{(boundary line for first constraint)}
\]
\[
3x + y = 90 \quad \text{(boundary line for second constraint)}
\]
Finding intersection points, we evaluate \( Z = 4x + y \) at feasible points and determine the maximum value.