If f(x) = 5x + 40, what is f(x) when x = -5?

Solution:

A function is a relation between a set of inputs which has one output each.

In other words, a function is a relation between inputs where each input is related exactly to one output.

These type of problem can be easily solved by substituting the given value of x in the given function.

Given: f(x) = 5x + 40

Substitute x = -5 in the given equation

f(-5) = 5(-5) + 40

By further calculation

f(-5) = -25 + 40

So we get,

f(-5) = 15

Therefore, f(x) when x = - 5 is 15.

If f(x) = 5x + 40, what is f(x) when x = -5?

Summary:

If f(x) = 5x + 40, then the value of f(x) when x = -5 is 15.