Algebraic expressions? Select ALL.
- A. 2*(x+3)+4
- B. 4=x^2
- C. x=3y+7
- D. 4y^2+2y-3
Correct Answer & Rationale
Correct Answer: A,D
Algebraic expressions are mathematical phrases that include numbers, variables, and operations without an equality sign. Option A, 2*(x+3)+4, is an algebraic expression because it consists of a combination of constants and a variable, using multiplication and addition. Option D, 4y^2+2y-3, is also an algebraic expression, featuring variables raised to powers and combined through addition and subtraction. Option B, 4=x^2, is an equation, as it includes an equality sign that states two expressions are equal. Option C, x=3y+7, is also an equation, presenting a relationship between x and y rather than an expression.
Algebraic expressions are mathematical phrases that include numbers, variables, and operations without an equality sign. Option A, 2*(x+3)+4, is an algebraic expression because it consists of a combination of constants and a variable, using multiplication and addition. Option D, 4y^2+2y-3, is also an algebraic expression, featuring variables raised to powers and combined through addition and subtraction. Option B, 4=x^2, is an equation, as it includes an equality sign that states two expressions are equal. Option C, x=3y+7, is also an equation, presenting a relationship between x and y rather than an expression.
Other Related Questions
P=2(L+W), P=48, W=L-4. Width?
- A. 10
- B. 12
- C. 20
- D. 24
Correct Answer & Rationale
Correct Answer: A
To find the width (W), start with the given perimeter formula \( P = 2(L + W) \). Substituting \( P = 48 \) gives \( 48 = 2(L + W) \), which simplifies to \( L + W = 24 \). Given \( W = L - 4 \), substitute this into the equation: \( L + (L - 4) = 24 \). This simplifies to \( 2L - 4 = 24 \), leading to \( 2L = 28 \) and \( L = 14 \). Thus, \( W = 14 - 4 = 10 \). Option B (12) does not satisfy the perimeter equation. Option C (20) and Option D (24) also do not fit the derived equations, confirming that W must be 10.
To find the width (W), start with the given perimeter formula \( P = 2(L + W) \). Substituting \( P = 48 \) gives \( 48 = 2(L + W) \), which simplifies to \( L + W = 24 \). Given \( W = L - 4 \), substitute this into the equation: \( L + (L - 4) = 24 \). This simplifies to \( 2L - 4 = 24 \), leading to \( 2L = 28 \) and \( L = 14 \). Thus, \( W = 14 - 4 = 10 \). Option B (12) does not satisfy the perimeter equation. Option C (20) and Option D (24) also do not fit the derived equations, confirming that W must be 10.
Measure pencil length?
- A. Millimeter
- B. Centimeter
- C. Meter
- D. Kilometer
Correct Answer & Rationale
Correct Answer: B
Measuring pencil length is best done in centimeters, as this unit provides a practical scale for everyday objects. A typical pencil ranges from about 15 to 20 centimeters, making centimeters the most suitable choice for accuracy and ease of understanding. Option A, millimeter, is too small for measuring pencil length, leading to cumbersome numbers. Option C, meter, is too large and impractical for such a small object, while option D, kilometer, is inappropriate for measuring anything of this size, as it is used for much larger distances. Thus, centimeters strike the perfect balance for this measurement.
Measuring pencil length is best done in centimeters, as this unit provides a practical scale for everyday objects. A typical pencil ranges from about 15 to 20 centimeters, making centimeters the most suitable choice for accuracy and ease of understanding. Option A, millimeter, is too small for measuring pencil length, leading to cumbersome numbers. Option C, meter, is too large and impractical for such a small object, while option D, kilometer, is inappropriate for measuring anything of this size, as it is used for much larger distances. Thus, centimeters strike the perfect balance for this measurement.
Driveway for two cars, width?
- A. 0.7
- B. 7
- C. 70
- D. 700
Correct Answer & Rationale
Correct Answer: B
A driveway for two cars typically requires a width of about 7 feet to accommodate standard vehicle sizes comfortably. Option A (0.7) is too narrow, as it would not allow even one car to fit. Option C (70) and Option D (700) are excessively wide for a residential driveway, making them impractical and unnecessary. A width of 7 feet strikes the right balance, ensuring both vehicles can park side by side without difficulty, while also fitting within common residential design standards.
A driveway for two cars typically requires a width of about 7 feet to accommodate standard vehicle sizes comfortably. Option A (0.7) is too narrow, as it would not allow even one car to fit. Option C (70) and Option D (700) are excessively wide for a residential driveway, making them impractical and unnecessary. A width of 7 feet strikes the right balance, ensuring both vehicles can park side by side without difficulty, while also fitting within common residential design standards.
Leslie descended 714 ft in 34 s, took 1 min 25 s to ground. Total distance?
- A. 1,270 feet
- B. 1,515 feet
- C. 1,785 feet
- D. 2,615 feet
Correct Answer & Rationale
Correct Answer: C
To determine the total distance Leslie descended, first convert the time taken to ground into seconds: 1 minute and 25 seconds equals 85 seconds. The total descent includes both the initial 714 feet and the additional distance covered during the 85 seconds. Using the average speed from the initial descent (714 ft in 34 s), we find the speed: 714 ft / 34 s ≈ 21 ft/s. Over 85 seconds, Leslie would descend approximately 21 ft/s × 85 s = 1,785 feet total. Option A (1,270 ft) underestimates the descent. Option B (1,515 ft) is also too low. Option D (2,615 ft) overestimates the total distance. Thus, C (1,785 ft) accurately reflects the total descent.
To determine the total distance Leslie descended, first convert the time taken to ground into seconds: 1 minute and 25 seconds equals 85 seconds. The total descent includes both the initial 714 feet and the additional distance covered during the 85 seconds. Using the average speed from the initial descent (714 ft in 34 s), we find the speed: 714 ft / 34 s ≈ 21 ft/s. Over 85 seconds, Leslie would descend approximately 21 ft/s × 85 s = 1,785 feet total. Option A (1,270 ft) underestimates the descent. Option B (1,515 ft) is also too low. Option D (2,615 ft) overestimates the total distance. Thus, C (1,785 ft) accurately reflects the total descent.