Easy Algebra Step-by-Step

198 Easy Algebra Step-by-Step

given value for x. In this setting, it is convenient to

think of x as being an input value and f(x) as being

an output value. You can also write the function

y = 3 x + 5 as f(x) = 3 x + 5, where y = f(x).

Problem Find the value of the function f(x) = 3 x + 5 at the given x value.

a. x = 3

b. x = 0

Solution

a. x = 3

Step 1. Check whether 3 is in the domain of the function.

The equation will generate real number values for each real number x.

The domain, then, is all real numbers. Thus, 3 is in the domain of f.

Step 2. Substitute the given number for x in the equation and evaluate.

f(3) = 3(3) + 5

f(3) = 14

b. x= 0

Step 1. Check whether 0 is in the domain of the function.

The equation will generate real number values for each real number x.

The domain, then, is all real numbers. Thus, 0 is in the domain of f.

Step 2. Substitute the given number for x in the equation and evaluate.

f(0) = 3(0) + 5

f(0) = 5

Problem Find the values of the function gx()x = xxx 32 + at the given x

value.

a. x= 4

b. x= 1

c. x= 8

The notation f(x) does not mean f

times x. It is a special notation for

the value of a function.