Chapter 6 - Systems of Equations and Inequalities - 6-4 Applications of Linear Systems - Practice and Problem-Solving Exercises - Page 392: 36

$d \leq -2.5$

Add $3$ to each side of the equation to move constants to the right side of the equation: $2d \geq 4d + 5$ Subtract $4d$ from each side of the equation: $-2d \geq 5$ Divide each side by $-2$. Remember that when we divide by a negative number, we need to reverse the sign: $d \leq -2.5$