1.
[tex]\begin{gathered} -5k\ge20 \\ \text{Divide by -5 both sides of the inequality:} \\ -\frac{5}{5}k\ge\frac{20}{-5} \\ k\ge-4 \end{gathered}[/tex]2.
[tex]\begin{gathered} \frac{d}{7}>3 \\ \text{Multiply both sides by 7} \\ \frac{d}{7}\cdot7>3\cdot7 \\ d>21 \end{gathered}[/tex]3.
[tex]\begin{gathered} 28<4(x+2) \\ 28<4x+8 \\ \text{Subtract both sides by 8} \\ 28-8<4x+8-8 \\ 20<4x \\ \text{Divide both sides by 4} \\ \frac{20}{4}<\frac{4x}{4} \\ 54.[tex]\begin{gathered} 5(n-3)\ge3(n+7) \\ 5n-15\ge3n+21 \\ 5n-3n\ge21+15 \\ 2n\ge36 \\ n\ge\frac{36}{2} \\ n\ge18 \end{gathered}[/tex]