EDGE Math 8

Example 1

If $f (x) = x^{2} - 1$ and $g (x) = x + 2,$ determine the following:

1.

(f + g) (2)

2.

(f - g) (- 1)

3.

(f \cdot g) (4)

Solution

1.	$f (2) = 2^{2} - 1 = 3$ and $g (2) = 2 + 2 = 4$
	$(f + g) (2) = f (2) + g (2)$ $= 3 + 4 = 7$

2.	$f (- 1) = {(- 1)}^{2} - 1 = 0$ and $g (- 1) = - 1 + 2 = 1$
	$(f - g) (- 1) = f (- 1) - g (- 1)$ $= 0 - 1 = - 1$

3.	$f (4) = 4^{2} - 1 = 15$ and $g (4) = 4 + 2 = 6$
	$(f \cdot g) (4) = f (4) \cdot g (4)$ $= 15 \cdot 6 = 90$