Hello There!
You have to put it into an equation:
2x + 3 = 12
Subtract 3 from both sides:
2x + 3 - 3 = 12 - 3
Simplify it:
2x = 9
Divide both sides by 2:
2x/2 = 9/2
Simplify it:
x = 4.5
Not too sure how she saw 4.5 birds but that's the answer.
Hope This Helps You!
Good Luck :)
- Hannah ❤