Question 398550
X=Y-17
Z=2Y+6
X+Y+Z=37
(Y-17)+Y+(2Y+6)=37
4Y-11=37
4Y=37+11
4Y=48
Y=48/4
Y=12 ANS. FOR THE MIDDLE NUMBER.
X=12-17
X=-5 ANS. FOR THE SMALLER NUMBER.
Z=2*12+6
Z=24+6
Z=30 ANS. FOR THE LARGER NUMBER. 
PROOF:
12-5+30=37
37=37