solve app question

[DrD]

If you are seeing check boxes in the Solve Numeric View, your version of this app is different than mine, (Per your screen caps). First solve for B, then solve for A ...

Solve App:

1. [Symb] to enter equations
2. E1: A=B+C [Uncheck box]
3. E2: B=C+D [Check box] // to solve this equation first ...

4. [Num] to enter known values
5. Put 2.1 in C:
6. Put 3 in D:
7. Press [Solve] soft key (B: is active box at this point.)
8. B: reports 5.10 // Computed value for B

9. [Symb] to select other equation
10. E1: [Uncheck box]
11. E2: [Check box]

12. [Num] to solve last equation
13. Press [Solve] soft key (A: is active box at this point.)
14. A: reports 7.20. // Computed value for B+C

A=B+C ==> A=5.10 + 2.10 ==> 7.20 ==> Q.E.D.