Question

How do I find the exponential function of the form `f(x)=ab^x` for which `f(-1)=10` and `f(0)=5`?

Answer 1

The answer is: `y=5(1/2)^x`

`f(-1)=10rArr10=ab^-1rArr10=a/brArra=10b`

`f(0)=5rArr5=ab^0rArr5=a*1rArra=5`.

So:
`a=5andb=1/2`.

The function is: `y=5(1/2)^x`.