Understanding functions

What do we call the values for x that make the denominator equal 0?

• Rationals

• Asymptotes

• Undefined $x\ne$

• Domain Restriction

Find the domain of the rational function f(x) = x / (x²-25)

• (- infinity, -5) U (5, infinity)

• (-infinity, -5) U (-5, 5) U (5, infinity)

• (- infinity, 5) U (5, infinity)

• (- infinity, 25) U (25, infinity)

A boat rental charges a $15 deposit fee plus $2 for each hour of use to rent a boat. The equation: y=2x+15. If Frank can afford to rent up to 9 hours, what is the domain of the situation? (x is number of hours and y is the cost).

• 0 < x < 9

• 0 < y < 9

• 0 < x < 33

• 0 < y < 33

• All Real Numbers

For the function (0,1), (1,-3), (2,-4), & (-4,1), which choice gives the correct domain (x values) & range (y values)?

• D: {0, 1, 2, -4}

  R: {1, -3, -4, 1}

• D: {-4, 0, 1, 2}

  R: {-4, -3, 1}

• D: {0, 1, 2, 3, 4}

  R: {1, -3, -4}

• D: {-4, -3, 1}

  R: {-4, 0, 1, 2}

The girls basketball team is having a fundraiser. The girls will receive $7 for each product, p, they sell. What is a reasonable domain and range for this function if they are required to sell at least 8 items but no more than 40 items?

• Discrete

  D: {56, 63, 70,...280}

  R: {8, 9, 10,...40}

• Discrete

  D: { 8, 9, 10,...40}

  R: {56, 63, 70,...280}

What is the domain of the function?

¿Cuál es el dominio de la función?

 $y=\sqrt{3x+5}$  

•  $x\ge-\frac{5}{3}$  

•  $x\ge-1.67$  

Answer explanation

An improper fraction is an exact answer. -1.67 is an approximate answer.
Una fracción impropia es una respuesta exacta. -1,67 es una respuesta aproximada.

What is the domain of y=3x²+4x-7?

• All Real Numbers (-∞, ∞)
• (-7, ∞)
• Cannot be determined
• (3, 4)

Find the range of the function: f(x)=2x-5, where -2≤x≤4.

• -9≤y≤3

• -2≤y≤4

• (-∞, ∞)

• -1≤y≤3