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. A couple dining at a restaurant receives a bill for $28.40. They wish to leave a 10% tip. Which of the following is the estimated gratuity?

A. $4.00
B. $6.00
C. $2.50
D. $3.00

Correct answer: D

Rationale: To calculate a 10% tip on a bill of $28.40, you would first find 10% of $28.40, which is $2.84. Since you typically round up when leaving a tip, the estimated gratuity would be $3.00. Option A is incorrect as it is too high for a 10% tip. Option B is incorrect as it is too high. Option C is incorrect as it is too low for a 10% tip. Therefore, the correct answer is $3.00.

3. Solve the following equation: 3(2y+50)−4y=500

A. y = 125
B. y = 175
C. y = 150
D. y = 200

Correct answer: B

Rationale: To solve the equation 3(2y+50)−4y=500, first distribute to get 6y+150−4y=500. Combining like terms results in 2𝑦 + 150 = 500. By subtracting 150 from both sides, we get 2y = 350. Dividing by 2 gives y = 175. Therefore, the correct answer is B. Choices A, C, and D are incorrect because they do not correctly follow the steps of distributing, combining like terms, and isolating the variable to solve for y.

4. How will the number 89632 be written if rounded to the nearest hundred?

A. 847.9
B. 900
C. 847.89
D. 847.896

Correct answer: B

Rationale: Rounding the number 89632 to the nearest hundred means keeping only two digits before the decimal point. The digit in the hundredth place is the digit in the thousands place of the original number, which is 6. Since 6 is equal to or greater than 5, the digit in the hundredth place, which is 3, gets rounded up. Thus, the number 89632 rounded to the nearest hundred is 900. Choice A, 847.9, rounds the number to the nearest tenth, not hundredth. Choice C, 847.89, adds an extra decimal place which is not correct for rounding to the nearest hundred. Choice D, 847.896, adds more decimal places than necessary for rounding to the nearest hundred.

5. Joshua needs more than 92 points to qualify for a scholarship. Each question is worth 4 points, and there are 30 questions. What inequality determines how many questions he must answer correctly?

A. 4x < 92
B. 4x > 92
C. 4x < 120
D. 4x > 120

Correct answer: B

Rationale: To determine the number of questions Joshua must answer correctly, we divide the total points required (92) by the points per question (4) to get 23. Since he needs more than 92 points, he must answer more than 23 questions correctly, which is represented by the inequality 4x > 92. Choices A, C, and D are incorrect because they do not accurately reflect the requirement for Joshua to answer more than 92 points' worth of questions.