Let the two numbers be x and y where x is greater than y.
So;
x + y = 3.1 ... (i)
2x - 3y = 7 ... (ii)
This forms a set of simultaneous equations (i) and (ii)
Solving the simultaneous equations by elimination;
We multiply (i) by 2 and (ii) by 1 to get:
2x + 2y = 6.2 ... (i)
2x - 3y = 7 ... (ii)
Subtracting (i) - (ii) we get;
5y = -0.8
y = -0.8/5 = -0.16
x = 3.1 - -0.16 = 3.26
The numbers are 3.26 and -0.16.
