Let the other number be 'y' and the other number be 'x'
We know that, y, is the result of subtracting 4 from the triple of 'x'
Translating this into a Mathematical sentence we have y = 3x - 4
We also know that x + y = 16
Writing y as 3x - 4, we have x + (3x - 4) = 16
Simplified as 4x-4=16
Correct answer: 4x-4=16
A + b + c = 12
c = (a + b) - 2.....c - a - b = -2
3a + 1 = 2c
add the first 2 equations
a + b + c = 12
-a - b + c = -2
------------------add
2c = 10
c = 5 <== longest side is 5
sub in 5 for c in the 3rd equation
3a + 1 = 2c
3a + 1 = 2(5)
3a + 1 = 10
3a = 10 - 1
3a = 9
a = 3 <== shortest side
now sub in 5 for c and 3 for a back into the first equation
a + b + c = 12
3 + b + 5 = 12
b + 8 = 12
b = 12 - 8
b = 4 <== other side