Verified Answer :

2n + 37 = 129
2n= 129-37
2n=92
n=\(\frac{92}{2}\)
  = 46

sum means add
twice a number is 2x

sum of twice a number and 37 is 129 means
2x+37=129
minus 37 both sides
2x=92
divide both sides by 2
x=46


the numbers i s46