EDGE Math 8

The notation $f (a)$ denotes the value of the function at $x = a .$ Note that this does not mean "f times a."

Example

If $f (x) = x^{2} - 1,$ evaluate the function at each given value.

f (0)

f (3)

f (a + 1)

Solution

1.	Substitute 0 for x in the equation $f (x) = x^{2} - 1.$

f (0) = 0^{2} - 1 = - 1

Thus,

f (0) = - 1.

2.	Substitute 3 for x in the equation $f (x) = x^{2} - 1.$

f (3) = 3^{2} - 1 = 9 - 1 = 8

Thus,

f (3) = 8.

3.	Substitute $(a + 1)$ for x in the equation $f (x) = x^{2} - 1.$

f (a + 1) = {(a + 1)}^{2} - 1

= a^{2} + 2 a + 1 - 1

= a^{2} + 2 a

Thus,

f (a + 1) = a^{2} + 2 a .