The first number is equal to 21.
The second number is equal to 23.
The third number is equal to 25.
x + x + 2 = 3(x + 4) - 31
Combine like terms
2x + 2 = 3(x + 4) - 31
Distributive property.
2x + 2 = 3x + 12 - 31
Combine like terms.
2x + 2 = 3x - 19
Subtract 2x from both sides.
2 = x - 19
Add 19 to both sides.
21 = x
The value of the first number is 21.