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. "is" in math means what?

A. Equals
B. Multiply
C. Subtract
D. Add

Correct answer: A

Rationale: In mathematics, "is" signifies equality, meaning that the values or expressions on both sides of the equation are the same. For example, in the equation 2+2=4, the phrase "2 + 2 is 4" indicates that the sum of 2 and 2 equals 4. "Multiply" refers to the operation of combining two numbers to obtain a product. For instance, in the expression 3×4, we multiply 3 by 4 to get 12. "Subtract" means to take one number away from another, resulting in a difference. For example, in 5−2, we subtract 2 from 5 to get 3. "Add" refers to the operation of combining two numbers to get a sum. For example, in 2+3, we add 2 and 3 to get 5.

3. How many feet are in a mile?

A. 1,000 ft
B. 5,280 ft
C. 2,000 ft
D. 10,000 ft

Correct answer: B

Rationale: The correct answer is B: 5,280 feet in a mile. This is a standard conversion used in the Imperial system of measurement. Choice A, 1,000 ft, is incorrect as it is a common misconception and not the accurate conversion. Choice C, 2,000 ft, is also incorrect. Choice D, 10,000 ft, is significantly higher than the actual conversion and is incorrect. Remember, when converting miles to feet, the accurate value is 5,280 feet in a mile.

4. Lauren must travel a distance of 1,480 miles to get to her destination. She plans to drive approximately the same number of miles per day for 5 days. Which of the following is a reasonable estimate of the number of miles she will drive per day?

A. 240 miles
B. 260 miles
C. 300 miles
D. 340 miles

Correct answer: C

Rationale: To estimate the number of miles Lauren will drive per day, the total distance can be rounded to 1,500 miles. Divide this by the number of days she plans to drive, which is 5. 1,500 miles / 5 days = 300 miles per day. Therefore, a reasonable estimate for the number of miles she will drive per day is 300. Choice A (240 miles) is too low, Choice B (260 miles) is slightly low, and Choice D (340 miles) is too high when considering the total distance and the number of days Lauren plans to drive.

5. How will 0.80 be written as a percent?

A. 40%
B. 125%
C. 90%
D. 80%

Correct answer: D

Rationale: To convert a decimal to a percent, you multiply by 100. Therefore, 0.80 * 100 = 80%. The correct answer is D. Choice A (40%) is incorrect as 0.80 is not equivalent to 40%. Choice B (125%) is incorrect as it is greater than 100%. Choice C (90%) is incorrect as it does not reflect the correct conversion of 0.80 to a percent.