[tex] \left \{ {{a = e + 5} \atop {(a-7) + (e - 7) = 23} \right. [/tex]
a = Anthony
e = Ellen
(e + 5 - 7) + (e - 7) = 23
e + -2 + e - 7 = 23
2e - 9 = 23
Add 9 on both sides.
2e = 32
Divide both sides by 2.
e = 16
a = 16 + 5
a = 21
30 - 21 = 9
In 9 years Anthony will be 30 years old.
