I need help for Mathematics question

In a quiz, Adam gets 8 marks less than Annabeth but 12 marks more than Fernandez. Total marks of 3 of them is 197. Find Adam's marks.

I tried but didn't really get the correct answer, that's why I asked. If you know the answer, please show me how you solved it. Thank you.

Assume adam gets X marks
Therefore Annabeth scored X+8
And Fernandez scored X-12

So we have X+X+8+X-12 = 197
3X = 201
X = 67
Adam = 67 Annabeth = 75 Fernandez = 55

If Adam's marks= x, Annabeth's= y, Fernandez's= z.
x+y+z= 197
Because x= y-8,
(y-8) + y + z= 197
2y+z= 205... (1)

Because x= 12+z
12+z + y + z= 197
2z + y = 185... (2)

(1)-(2)= z= 55, y= 75, x= 67

So, Adam's marks is 67

(Adam + 8) = Annabeth
(Adam - 12) = Fernandez
Adam + (Adam + 8) + (Adam - 12) = 197
3 Adam - 4 = 197
3 Adam = 201
Adam = 201/3 = 67

Check: (67 + 8) + 67 + (67 - 12 ) = 75 + 67 + 55 = 197

For math you need God's help.
:)
adam= X
Annabeth=Y
Fernandez=Z
X-8=Y
X+12=Z
X+Y+Z=197
X=?
{{X-8=Y]+[X+12=Z]}=> 2X+4=Y+Z *
X+(Y+Z)=197 => X+(2X+4)=197 => 3X=193 => X=193/3=64.33