Answer :
So,
Home ---- gym = 3.6 mi.
gym ---- store = .7 mi.
store ----- home = x
3.6 + .7 + x = 7.2 mi.
Collect Like Terms
4.3 + x = 7.2
Subtract 4.3 from both sides
x = 2.9
The distance from the store to her home is 2.9 miles.
Home ---- gym = 3.6 mi.
gym ---- store = .7 mi.
store ----- home = x
3.6 + .7 + x = 7.2 mi.
Collect Like Terms
4.3 + x = 7.2
Subtract 4.3 from both sides
x = 2.9
The distance from the store to her home is 2.9 miles.