Question

If `F( t ) = 8- 9t - 4t ^ { 2}`, what is `F(-1)`?

Answer 1

`F(-1)=13`

Explanation:

A function is a set of rules that takes some value and maps or associates it with another. Here, the "rules" of our function `F` take some input value `t` and map it to a new value, `F(t)` (read "`F` of `t`" or "the value of `F` at `t`"), according to the rule `8-9t-4t^2`. To find where a particular value `t` will be mapped to under those rules, we just need to run it through the expression.

In this case, where `t=-1`, the value `F` will map `t` to will be `8-9(-1)-4(-1)^2`. Simplifying that expression, we get:

`F(t)=8+9-4=17-4=13`