Answer:
Ronda is 37 and Brandon is 46
Explanation:
x - the age of Ronda
x + 9 - the age of Brandon
x + 4 - the age of Ronda in 4 years
x + 9 + 4 - the age of Brandon in 4 years
x + 4 + x + 9 + 4 - the sum of their ages in 4 years
x + 4 + x + 9 + 4 = 91
2x + 17 = 91 {subtract 17 from both sides}
2x = 74 {divide both sides by 2}
x = 37
x + 9 = 37 + 9 = 46