which equation is not a function

ATI TEAS 7

TEAS Math Practice Test

1. Which of the following equations does not represent a function?

A. y = x^2
B. y = sqrt(x)
C. x = y^2
D. y = 2x + 1

Correct answer: C

Rationale: An equation represents a function if each input (x-value) corresponds to exactly one output (y-value). In the equation x = y^2, for a single x-value, there are two possible y-values (positive and negative square root), violating the definition of a function. This violates the vertical line test, where a vertical line intersects the graph in more than one point for non-functions. Choices A, B, and D all pass the vertical line test and represent functions, making them incorrect answers.

2. If 9.5% of a town's population of 51,623 people voted for a proposition, approximately how many people voted for the proposition?

A. 3000
B. 5000
C. 7000
D. 10000

Correct answer: B

Rationale: To find the approximate number of people who voted for the proposition, multiply the town's population by the percentage that voted: 51,623 * 9.5% = 51,623 * 0.095 ≈ 4,904. Therefore, approximately 5,000 people voted for the proposition. Choice A (3000), C (7000), and D (10000) are incorrect because they do not accurately represent 9.5% of the town's population.

3. Which of the following is not a negative value?

A. (−3)(−1)(2)(−1)
B. 14 – 7 + (−7)
C. 7 – 10 + (−8)
D. −5(−2)(−3)

Correct answer: B

Rationale: To identify the negative value, simplify each expression. A) simplifies to 6 which is positive. B) simplifies to 0 which is neither positive nor negative. C) simplifies to -11 which is negative. D) simplifies to -30 which is negative. Therefore, only choice B results in a non-negative value, making it the correct answer.

4. During week 1, Nurse Cameron works 5 shifts. During week 2, she worked twice as many shifts as she did in week 1. In week 3, she added 4 shifts to the number of shifts worked in week 2. Which equation describes the number of shifts Nurse Cameron worked in week 3?

A. Shifts = (2)(5) + 4
B. Shifts = (4)(5) + 2
C. Shifts = 5 + 2 + 4
D. Shifts = (5)(2)(4)

Correct answer: A

Rationale: During week 1, Nurse Cameron worked 5 shifts. In week 2, she worked twice as many shifts as in week 1, which is 10 shifts. In week 3, she added 4 shifts to the number of shifts worked in week 2. Therefore, the total shifts in week 3 can be calculated as (2)(5) + 4 = 10 + 4 = 14 shifts. Choice A correctly represents this calculation. Choices B, C, and D are incorrect because they do not accurately reflect the given scenario and the steps needed to find the total shifts in week 3.

5. The cost, in dollars, of shipping x computers to California for sale is 3000 + 100x. The amount received when selling these computers is 400x dollars. What is the least number of computers that must be shipped and sold so that the amount received is at least equal to the shipping cost?

A. 10
B. 15
C. 20
D. 25

Correct answer: B

Rationale: To find the least number of computers that must be shipped and sold so that the amount received is at least equal to the shipping cost, we set up the inequality 400x >= 3000 + 100x. Simplifying this inequality gives 300x >= 3000, and dividing by 300 results in x >= 10. Therefore, at least 15 computers must be shipped and sold to cover the shipping cost, making choice B the correct answer. Choices A, C, and D are incorrect as they represent numbers less than 15, which would not cover the shipping cost.