Answer:
1/2b - 5 (the third one)
Step-by-step explanation:
"Denni is five years less..."
this tells us we will need to be subtracting five, which knocks out the other answers.
"..one-half his brothers age."
since b represents the age of his brother, one half his brothers age is 1/2b
That leaves us with 1/2b - 5
