let 'x' be Liza's age now
'y' be Melanie's age now
'z' be Lakan's age now
'x-3' be Liza's age 3 years ago
x = 2 + y ----equation 1
y = 3 + z ----equation 2
x + y + z = 71 ----equation 3
from equation 2:
y = 3 + z
z = y - 3 ----equation 2'
substitute equations 1 and 2' to equation 3
x + y + z = 71
(2 + y) + y + (y - 3) = 71
3y = 71 + 3 - 2
3y = 72
y = 24
Liza's age now:
x = 2 + y
x = 2 + 24
x = 26 yrs old
Liza's age 3 years ago:
x - 3 = 26 - 3
= 23 years old
