(f+g)(x) = f(x) + g(x)

= (x² + 12) + (3x - 7)

= ​x² + 12 + 3x - 7

= x²​ + 3x + 12 - 7

​

(f+g)(x) = x² + 3x + 5​

Given f(x) = x² + 12 and

g(x) = 3x - 7, find

​

(f+g)(x) = f(x) + g(x)

​

This simply means to add the two functions and combine like terms.​

Addition:

​

Adding and Subtracting Functions

Please take notes on the above information.

(f-g)(x) = f(x) - g(x)

= (x² + 12) - (3x - 7)

= (x²​ + 12) +(-3x + 7)

= ​x² + 12 - 3x + 7

= x²​ - 3x + 12 + 7

​

(f+g)(x) = x² - 3x + 19​

Given f(x) = x² + 12 and

g(x) = 3x - 7, find

​

(f-g)(x) = f(x) - g(x)

​

For subtraction, change the signs of each term in the functions, Then combine like terms.​

Subtraction:

​

Adding and Subtracting Functions

Please take notes on the above information.

(f⋅g)(x)= f(x) ⋅ g(x)

= (x² -3x - 40)(x + 5)

= x²​(x+5) - 3x(x+5) - 40(x+5)

= x³​ +5x² -3x² +15x -40x -200

= x³​ - 2x² - 25x - 200

​

(f⋅g)(x) = x³ - 2x² - 25x -200​

Given f(x) = x² - 3x - 40 and

g(x) = x + 5, find

​

(f⋅g)(x) = f(x) ⋅ g(x)

​

For multiplication, multiply each term in the first function by each term in the second function (F.O.I.L). Then combine like terms.​

Multiply:

​

Multiply and Divide Functions

Please take notes on the above information.

(f/g)(x)= f(x)/g(x)

= (x² - 3x - 40)/(x + 5)

= (x² - 3x - 40)÷(x + 5)

​-5| 1 -3 -40

_____-5___40_ ​

​ 1 -8 | 0

(f/g)(x) = x - ​8

Given f(x) = x² - 3x - 40 and

g(x) = x + 5, find

​

(f/g)(x) = f(x)/g(x)

​

For division, make a fraction with one of the functions over the other. You can use synthetic division to divide the numberator by the denomiator.

Divide:

​

Multiply and Divide Functions

Please take notes on the above information.

​Example 1

(f⋄g)(x) = f[g(x)]

= 3( ) - 12

= 3(10x) - 12

​ = 30x - 12

​​

(f⋄g)(x) = 30x - 12

Given f(x) = 3x - 12 and

g(x) = 10x find

​

(f⋄g)(x) = f[g(x)]

​

For the composition, start by writing the first function, with an open set of parenthesis instead of the variable. In the paraenthsis, write the other function.

Composition:

​

Composition of Functions

Please take notes on the above information.

​Example 2

(g⋄f)(x) = g[f(x)]

= 10( )

= 10(3x - 12)

= 30x - 120

​​

(g⋄f)(x) = 30x - 120

Given f(x) = 3x - 12 and

g(x) = 10x find

​

(g⋄f)(x) = g[f(x)]

​

This is the same as Example 1, but you start with second function and you plug in the first equation.

Composition:

​

Composition of Functions

Please take notes on the above information.