1 - 2/3y = 6/15 Isolate/get y by itself, first subtract 1 on both sides
-2/3y = 6/15 - 1 [to combine fractions, they need to have the same denominator]
-2/3y = 6/15 - 15/15
-2/3y = -9/15 Multiply the inverse of -2/3, which is -3/2 on both sides to get y by itself
y = 27/30 Simplify
y = 9/10