Question 925102
P, Preston
L, Lillie
A, Anna


{{{system(P=L+5,L=A+2,P+L+A=11)}}}


Various ways to solve the system.  Notice the first two equations both share the variable, L only.  These two equations give  P=L+5 and A=L-2.  Use these to substitute for P and for A in the age sum, the third equation; and solve for the value of L.