Algebra II : Introduction to Functions

Study concepts, example questions & explanations for Algebra II

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Example Questions

Example Question #171 : Functions And Graphs

Determine the value of  if:  .

Possible Answers:

Correct answer:

Explanation:

Substitute the values of  into the expression.

In order to subtract these fractions, we will need a least common denominator.

Multiply the denominators together for the LCD.  Convert the two fractions.

Subtract the numerators now that the denominators are common.

The answer is:  

Example Question #172 : Functions And Graphs

Determine the value of  if:  

Possible Answers:

Correct answer:

Explanation:

Given the expression  and the assigned values, substitute the values into the expression.

Simplify this expression by order of operations.

The answer is:   

Example Question #41 : Function Notation

Evaluate  if  and 

Possible Answers:

Correct answer:

Explanation:

Substitute the known values into the expression.

Simplify the expression.

The answer is:  

Example Question #691 : Algebra Ii

If  and , what is 

Possible Answers:

Correct answer:

Explanation:

Substitute the assigned values into the expression.

Simplify the negative exponents by rewriting both terms as fractions.

Simplify the fractions.

The answer is:  

Example Question #173 : Functions And Graphs

If , what must  be?  

Possible Answers:

Correct answer:

Explanation:

Substitute the known value of  into the equation.

Simplify the equation.

Solve the right side by distribution.

Add 42 on both sides.

Divide by six on both sides.

The answer is:  

Example Question #47 : Function Notation

If , what must  equal in ?

Possible Answers:

Correct answer:

Explanation:

The term  means that  when .

Substitute the terms in the function to solve for .

Solve for .

Subtract 10 on both sides.

Divide by negative one to eliminate the negative signs.

The answer is:  

Example Question #41 : Function Notation

Which of the following is the equation of a vertical asymptote of the graph of the function  ?

(a) 

(b) 

(c) 

Possible Answers:

(b) and (c) only 

(a) only

(c) only

(b) only

All three of (a), (b), and (c)

Correct answer:

(b) and (c) only 

Explanation:

The vertical asymptote(s) of the graph of a rational function such as  can be found by evaluating the zeroes of the denominator after the rational expression is reduced. The expression is in simplest form, so set the denominator equal to 0 and solve for :

Add 16 to both sides:

Take the positive and negative square roots:

or 

The graph of  has two vertical asymptotes, the graphs of the lines  and .

Example Question #171 : Introduction To Functions

If  and  what is ?

Possible Answers:

Correct answer:

Explanation:

 is a composite function which means that the inside function is plugged into the outside function. So in this case,  is plugged into . In other words, replace the  expression each time there is an  in the  expression. 

 

In this case  would be plugged into each  in the  expression. See below:

 

 

This is then simplified to:

 

 

And then further simplified to:

 

Example Question #1 : Transformations

How is the graph of  different from the graph of ?

Possible Answers:

is wider than and is shifted to the right 3 units

is narrower than and is shifted down 3 units

is narrower than and is shifted to the left 3 units

is narrower than and is shifted up 3 units

is wider than and is shifted down 3 units

Correct answer:

is narrower than and is shifted down 3 units

Explanation:

Almost all transformed functions can be written like this:

where is the parent function. In this case, our parent function is , so we can write  this way:

Luckily, for this problem, we only have to worry about and .

represents the vertical stretch factor of the graph.

  • If is less than 1, the graph has been vertically compressed by a factor of . It's almost as if someone squished the graph while their hands were on the top and bottom. This would make a parabola, for example, look wider.
  • If is greater than 1, the graph has been vertically stretched by a factor of . It's almost as if someone pulled on the graph while their hands were grasping the top and bottom. This would make a parabola, for example, look narrower.

represents the vertical translation of the graph.

  • If is positive, the graph has been shifted up units.
  • If is negative, the graph has been shifted down units.

 

For this problem, is 4 and is -3, causing vertical stretch by a factor of 4 and a vertical translation down 3 units.

Example Question #2 : Transformations

Which of the following transformations represents a parabola shifted to the right by 4 and halved in width?

Possible Answers:

Correct answer:

Explanation:

Begin with the standard equation for a parabola: .

Horizontal shifts are represented by additions (leftward shifts) or subtractions (rightward shifts) within the parenthesis of the  term. To shift 4 units to the right, subtract 4 within the parenthesis.

The width of the parabola is determined by the magnitude of the coefficient in front of . To make a parabola narrower, use a whole number coefficient. Halving the width indicates a coefficient of two.

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