64 is 4 times the difference between Sarah's age, a, and 44. Assume Sarah is older than 44.

The phrase difference between means we subtract 44 from a:
a - 44

The phrase 64 is means an equation, so we set a - 44 equal to 64
a - 44 = 64 <-- This is our algebraic expression

If you want to solve for a, then we type this expression into our search engine and get:
a = 108

ncG1vJloZrCvp2O6osDHnJylnZKntrXFjZympmeTpLquwc2iq7JnpJ2%2Fpq3DrGZvbF2ewG6AjK2gpp2jYsGpsYydoJ%2Belaeyr6%2FEZpmerKeasq950pqpmqCjYq6osYyaZJqmlGKBdXnArKqupZViwKK%2BwKFkoqtdpLmlsdFmq6GZnmKBdXqRa2ppZw%3D%3D