Question

How to do this question, finding the value of a?

Answer 1

`a=-3`

Explanation:

We know if `f(x)=2x+3`, then

`f(x+y)=2(x+y)+3`

`=2x+2y+3`

`=(2x+3)+(2y+3)-3`

`=f(x)+f(y)-3`

Thus `a=-3`