Solve the equation just like you for any ordinary equation. Leave the inequality sign as it should be and transpose like terms.
r + 3 ≥ 7
r ≥ 7 - 3
r ≥ 4
Thus, the value of r must be less than or equal to 4. Its range would be (-∞, 4].
I hope I was able to explain it clearly. Have a good day.
