Lindsay is 5 years younger than Mark. Seven years ago, the sum of their ages was
31.
let l be Lindsay's age and let m be Mark's age. Which system of equations represents this situation?


l−7=(m−7)+5
l+m=31




l=m+5

(l−7)+(m−7)=31




l−7=(m−7)−5

l+m=31


l=m−5

(l−7)+(m−7)=31