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. What must you always use in all math?

A. PEMDAS
B. Variables
C. Conversion factors
D. Estimation

Correct answer: A

Rationale: The correct answer is A: PEMDAS. PEMDAS stands for the order of operations: Parentheses, Exponents, Multiplication and Division (left to right), Addition and Subtraction (left to right). It is a fundamental rule to follow in mathematics to ensure calculations are done correctly. Choices B, C, and D are incorrect as they do not encompass the essential rule that PEMDAS provides for solving mathematical expressions.

3. A lab technician took 500 milliliters of blood from a patient. The technician used 1/6 of the blood for further tests. How many milliliters of blood were used for further tests? Round your answer to the nearest hundredth.

A. 83
B. 83.3
C. 83.33
D. 83.34

Correct answer: C

Rationale: To find 1/6 of 500, multiply 500 by 1/6: (500)(1/6) = 500/6 = 83.33. Converting the fraction to a decimal gives 83.33. Rounding this to the nearest hundredth results in 83.33. Therefore, 83.33 milliliters of blood were used for further tests. Choice A is incorrect as it does not consider the decimal value of the fraction. Choice B is incorrect as it rounds to the tenths place, not the nearest hundredth. Choice D is incorrect as it rounds up unnecessarily, as the correct answer should be rounded to 83.33.

4. Simplify the following expression: 1.034 + 0.275 - 1.294

A. 0.015
B. 0.15
C. 1.5
D. -0.15

Correct answer: A

Rationale: To simplify the expression, begin by adding 1.034 and 0.275, which equals 1.309. Then, subtract 1.294 from the sum: 1.309 - 1.294 = 0.015. Therefore, the correct answer is 0.015. Choice B (0.15) is incorrect as it does not reflect the accurate calculation. Choice C (1.5) is incorrect as it is not the correct result of the expression simplification. Choice D (-0.15) is incorrect as it represents a different value than the correct outcome of the expression simplification.

5. A triangle has dimensions of 9 cm, 4 cm, and 7 cm. The triangle is reduced by a scale factor of x. Which of the following represents the dimensions of the dilated triangle?

A. 8.25 cm, 3.25 cm, 6.25 cm
B. 4.5 cm, 2 cm, 3.5 cm
C. 6.75 cm, 3 cm, 5.25 cm
D. 4.95 cm, 2.2 cm, 3.85 cm

Correct answer: C

Rationale: When reducing a figure by a scale factor, each dimension is multiplied by the same scale factor. In this case, the scale factor is not provided in the question. To find the scale factor, you would divide the new lengths of the sides by the original lengths. The scaled-down triangle's dimensions are the original dimensions multiplied by the scale factor. By performing the calculations, the dimensions of the dilated triangle are 6.75 cm, 3 cm, and 5.25 cm, which matches choice C. Choices A, B, and D have incorrect dimensions as they do not result from the correct application of the scale factor to the original triangle's dimensions.