Solve the system of equations using substitution or elimination by addition.
x + y = 0.5
0.7x + 0.6y = 0.31
select the correct choice below and if necessary, fill in the answer box to complete your choice.
a. the solution is (type an ordered pair.)
b. there are infinitely many solutions.
c. there is no solution.

A. The unique solution to the system is

Step-by-step explanation:

 You can follow these steps to solve the system of equation by the Elimination Method:

- Multiply the first equation by -0.7, then add both equations and solve for "y":

- Substitute the value of "y" into any original equation to find the value of "x". Then:

 Therefore, the unique solution to the system is

step-by-step explanation: