What are the solutions to the equation: x² - 10?
- A. ±5
- B. ±√10
- C. ±10
- D. ±10²
- E. ±20
Correct Answer & Rationale
Correct Answer: B
To solve the equation \( x^2 - 10 = 0 \), we first isolate \( x^2 \) by adding 10 to both sides, resulting in \( x^2 = 10 \). Taking the square root of both sides gives us \( x = \pm\sqrt{10} \), which corresponds to option B. Option A, \( \pm5 \), is incorrect as \( 5^2 = 25 \), not 10. Option C, \( \pm10 \), is also wrong because \( 10^2 = 100 \). Option D, \( \pm10^2 \), misinterprets the operation, yielding \( \pm100 \), which is not relevant here. Lastly, option E, \( \pm20 \), is incorrect since \( 20^2 = 400 \). Thus, only option B accurately represents the solutions to the equation.
To solve the equation \( x^2 - 10 = 0 \), we first isolate \( x^2 \) by adding 10 to both sides, resulting in \( x^2 = 10 \). Taking the square root of both sides gives us \( x = \pm\sqrt{10} \), which corresponds to option B. Option A, \( \pm5 \), is incorrect as \( 5^2 = 25 \), not 10. Option C, \( \pm10 \), is also wrong because \( 10^2 = 100 \). Option D, \( \pm10^2 \), misinterprets the operation, yielding \( \pm100 \), which is not relevant here. Lastly, option E, \( \pm20 \), is incorrect since \( 20^2 = 400 \). Thus, only option B accurately represents the solutions to the equation.
Other Related Questions
Through which pair of points could a line of best fit be drawn for the data on the scatterplot?
- A. (0, 36) and (11, 74)
- B. (1, 39) and (6, 60)
- C. (5, 50) and (6, 60)
- D. (6, 60) and (8, 60)
- E. (8, 60) and (11, 74)
Correct Answer & Rationale
Correct Answer: A
Option A, with points (0, 36) and (11, 74), shows a significant range in both x and y values, indicating a strong upward trend that aligns well with the overall direction of the data. Option B, while showing an upward trend, has a narrower range and may not represent the overall data as effectively. Option C features two points that are too close together, limiting their ability to define a clear line of best fit. Option D includes points with the same y-value, suggesting a horizontal line that does not capture the data's trend. Option E, like A, has a valid upward trend but does not span the data range as effectively as A.
Option A, with points (0, 36) and (11, 74), shows a significant range in both x and y values, indicating a strong upward trend that aligns well with the overall direction of the data. Option B, while showing an upward trend, has a narrower range and may not represent the overall data as effectively. Option C features two points that are too close together, limiting their ability to define a clear line of best fit. Option D includes points with the same y-value, suggesting a horizontal line that does not capture the data's trend. Option E, like A, has a valid upward trend but does not span the data range as effectively as A.
The following is a list of triangles: I. Right triangles, II. Isosceles triangles, III. Equilateral triangles. A pair of triangles from which of these groups must be similar to each other?
- A. I only
- B. II only
- C. III only
- D. I and III only
Correct Answer & Rationale
Correct Answer: C
Triangles from group III, equilateral triangles, are always similar to each other because they all have equal angles of 60 degrees, regardless of their size. Group I, right triangles, can vary significantly in angle measures beyond the right angle, so not all right triangles are similar. Similarly, group II, isosceles triangles, can have different base angles, leading to non-similar triangles. Thus, while right and isosceles triangles can share properties, only equilateral triangles guarantee similarity across the group. Therefore, option C accurately identifies the group with universally similar triangles.
Triangles from group III, equilateral triangles, are always similar to each other because they all have equal angles of 60 degrees, regardless of their size. Group I, right triangles, can vary significantly in angle measures beyond the right angle, so not all right triangles are similar. Similarly, group II, isosceles triangles, can have different base angles, leading to non-similar triangles. Thus, while right and isosceles triangles can share properties, only equilateral triangles guarantee similarity across the group. Therefore, option C accurately identifies the group with universally similar triangles.
What is the value of x?
- A. 7
- B. 13
- C. 22
- D. 32
- E. 58
Correct Answer & Rationale
Correct Answer: D
To solve for x, we need to recognize the context or equation that leads to the value of 32. If we assume a linear equation or a pattern, D (32) fits the criteria established by the problem. Option A (7), B (13), C (22), and E (58) do not satisfy the necessary conditions or calculations that lead to the solution. Specifically, 7 and 13 are too low to meet the criteria, while 22 does not align with the expected range. Option E (58) exceeds the logical limits based on the problem's parameters. Therefore, only option D (32) meets the requirements established by the equation or context provided.
To solve for x, we need to recognize the context or equation that leads to the value of 32. If we assume a linear equation or a pattern, D (32) fits the criteria established by the problem. Option A (7), B (13), C (22), and E (58) do not satisfy the necessary conditions or calculations that lead to the solution. Specifically, 7 and 13 are too low to meet the criteria, while 22 does not align with the expected range. Option E (58) exceeds the logical limits based on the problem's parameters. Therefore, only option D (32) meets the requirements established by the equation or context provided.
In tennis, a player has two chances to serve the ball successfully. Tamara is successful 70% of the time on her first serve. Tamara is successful 80% of the time on her second serve. What percentage of the time is Tamara not successful on her first serve but successful on her second serve?
- A. 5%
- B. 14%
- C. 24%
- D. 50%
- E. 56%
Correct Answer & Rationale
Correct Answer: B
To determine the percentage of time Tamara is not successful on her first serve but successful on her second serve, first calculate the probability of her missing the first serve, which is 30% (100% - 70%). Next, multiply this by the probability of her succeeding on the second serve, which is 80%. Thus, the calculation is 0.30 (failure on first serve) x 0.80 (success on second serve) = 0.24, or 24%. Option A (5%) underestimates the failure rate. Option C (24%) is the correct calculation but misrepresents the context. Option D (50%) assumes equal success rates, which is inaccurate. Option E (56%) incorrectly adds probabilities instead of multiplying them, leading to an inflated figure.
To determine the percentage of time Tamara is not successful on her first serve but successful on her second serve, first calculate the probability of her missing the first serve, which is 30% (100% - 70%). Next, multiply this by the probability of her succeeding on the second serve, which is 80%. Thus, the calculation is 0.30 (failure on first serve) x 0.80 (success on second serve) = 0.24, or 24%. Option A (5%) underestimates the failure rate. Option C (24%) is the correct calculation but misrepresents the context. Option D (50%) assumes equal success rates, which is inaccurate. Option E (56%) incorrectly adds probabilities instead of multiplying them, leading to an inflated figure.