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
