You have a system of equations

.
1. Substitude right side of second equation into the left side of the first equation:

.
2. Solve this equation:

.
3. Find y:
for

,
for

.
4. The solutions of the system are: (3,-12) and (5,-24).
Answer: Correct choice is A.
Answer:
12
Step-by-step explanation:
Let n = the number.
2n - 7 = n + 5
n = 12
Let’s check if we got the right answer by substituting 12 for n into the original equation.
2*12 - 7 = 12 + 5
24 - 7 = 17
17 = 17