Question

como eu faço 2y-9=10-y

Answer 1

2y-9=10-y
2y+y=10+9
3y=19
y=19/3

Answer 2

$2y-9=10-y\to \\\\ 2y+y=10+9\to \\\\ 3x=19\to \\\\ \boxed{y= \frac{19}{3} }$