FUNCTIONS;F(x) - Daily Math Guide

## FUNCTIONS

A function is a mathematical expression, usually denoted by f(x) which read as the function of x. The "f(x)" with "x" is the input for the output to behave of what certain value will be replaced to "x" as input. Let say, the function equation f(x) = 3x-1. The "x" in f(x) should be replaced by any number as an input. By illustration, let x=2, then the f(x) = 3x-1 will now became f(2) = 3*2-1.The 3x-1 in f(x) = 3x-1, will at the same time behaved with f(x). Now, executing the relationship of f(x) = 3x-1 with respect to the value of x as 2, then f(2) = 3*2-1 =6-1 = 5. Thus f(2) = 5.

More illustrative examples:

1. Given that f(x) = 2x +1:

Evaluate:

a). f(1)

b. f(-1)

c) f(-3)

Solution for:

a) f(x) = 2x +1; @ x=1

f (1) =2*1+1
f (1) = 2 + 1

b). f(x) = 2x +1; @ x=-1

f(-1) =2(-1)+1
f(-1) = -2 + 1

c). f(x) = 2x +1; @ x=-3

f(-3) =2(-3)+1
f(-3) = -6 + 1

2). Given that g(x) = 3x -2:

Evaluate:

a). g(0)

b.  g(-2)

c)   g(3)

Solution for:

a). g(x) = 3x -2;@ x =0

g(0) = 3(0) - 2
g(0) = 0 - 2

b). g(x) = 3x -2; @ x =-2

g(-2) = 3(-2) -2
g(-2) = -6 - 2

c). g(x) = 3x -2; @ x =3

g(-3) = 3(-3) -2
g(-3) = -9 - 2

Exercises. Evaluate each given functions:

Given:

Let: A) f (x) = x2 – 3x + 2,

B) g (x) =  2x2 + 3x - 1

C) h (x) =  x2 – 3

Evaluate:

1. f (-2) = ___________

2. g (-1) = ___________

3. f ( 0 ) = ___________

4. g (2a) = ___________

5. f  - c) = ___________

6. h (2z) = ___________

7. f (- a b) = __________

8. f [ h (-2) ] = ________

9. g [ f (2a) ] = ________

10. f { g [ h (-2) ] } = _________

(Please comment for improvement. thank you)
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