What is the value of y in the arithmetic sequence y + 6, 12, 3y?
y+6+x=12, y+x=6
12+x=3y, 3y-x=12
4y=18
y=9/2
JP
$(y+6) + n = 12$
$12 + n = 3y$
$y + n = 6$
$n = 3y - 12$
$y + (3y - 12) = 6$
$4y - 12 = 6$
$4y = 18$
$\boxed{y = 4.5}$
+876 
