Question

Jason's age is 1 2 of his brother's age. His brother's age can be represented by the expression 12a - 9. Write an expression that can be used to represent the sum of their ages. A) 12a - 5.5 B) 18a - 13.5 C) 18a + 21 Eliminate D) (12a-9) 2

Answer 1

B. 18a-13.5   The expression 6a-4.5 can represent Jason's age. (Because this is half of the given expression for his brother.) When 6a-4.5 is added to the age of his bother, 12a-9, the result is the function 18a-13.5.

Answer 2

`18a - 13.5`

Explanation:

Jason's age is
`(1)/(2)` of his brother's age.

Brother age is
`12a-9`

Sum of their ages = Age of Jonson + age of his brother

Jonson's age = half of his brother age

`Jonson's \ age=(12a-9)/(2)`

Sum of their ages =
`(12a-9)/(2)+12a-9`

Take common denominator 2

`(12a-9)/(2)+(24a-18)/(2)`

`(36a-27)/(2)`

`18a - 13.5`