What is the value of 7 + 5 × 3 − 4?
- 12
- 32
- 18 Correct answer.
- 19
Explanation
Order of operations requires multiplication before addition and subtraction, so 5 × 3 = 15 first. Then 7 + 15 − 4 = 18.
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Order of operations requires multiplication before addition and subtraction, so 5 × 3 = 15 first. Then 7 + 15 − 4 = 18.
The additive identity is the number that leaves any integer unchanged when added to it. Since a + 0 = a for every integer a, the additive identity is 0.
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The expression is a difference of squares, a² − b² = (a − b)(a + b). With a = x and b = 3, it factors as (x − 3)(x + 3).
By the Pythagorean theorem, the hypotenuse c satisfies c² = 6² + 8² = 36 + 64 = 100. Taking the positive square root gives c = 10.
An arithmetic sequence adds a constant difference each step; here the difference is 4. Adding 4 to the last term 15 gives 19.
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Let the numbers be a and b with a + b = 20 and a − b = 4. Adding the equations gives 2a = 24, so a = 12.
The area of a circle is πr². Substituting r = 7 and π ≈ 22/7 gives (22/7) × 49 = 22 × 7 = 154.
Subtract 2 from both sides to get 3x < 9, then divide by the positive number 3, which keeps the inequality direction, giving x < 3.
There are 36 equally likely outcomes. The sums equal to 7 occur in 6 ways: (1,6), (2,5), (3,4), (4,3), (5,2), (6,1). Thus the probability is 6/36 = 1/6.
Absolute value gives the distance from zero, so |−9| = 9 and |4| = 4. Their sum is 9 + 4 = 13.
We need two numbers whose product is 6 and whose sum is 5; these are 2 and 3. So x² − 5x + 6 = (x − 2)(x − 3) = 0, giving x = 2 or x = 3.
The angles of a triangle sum to 180°. The third angle is 180° − 45° − 65° = 70°.
A geometric sequence has nth term a·r^(n−1), where a = 2 is the first term and r = 3 is the common ratio. For n = 10, the term is 2 × 3⁹.
Substitute x = −2: 2(−2)² − 3(−2) + 1 = 2(4) + 6 + 1 = 8 + 6 + 1 = 15.
The volume of a cone is (1/3)πr²h. Substituting r = 3 and h = 4 gives (1/3)π(9)(4) = 12π.
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If the roots are positive integers with product 8, the possible pairs are (1,8), (2,4). Their sums are 9 and 6, so b = −(sum) equals −9 or −6. Since the options include −6, that is the valid value.
A power means repeated multiplication: 3⁴ = 3 × 3 × 3 × 3. Multiplying gives 9 × 9 = 81.
For the standard angle 60°, the cosine equals the adjacent side over the hypotenuse in a 30-60-90 triangle, giving 1/2. This is one of the exact values worth memorizing.
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Subtract 9 from both sides to get 5x = 25, then divide both sides by 5 to obtain x = 5.
We need two numbers whose product is 12 and whose sum is 7; those numbers are 3 and 4. Hence x² + 7x + 12 = (x + 3)(x + 4).
The diagonal of a rectangle forms a right triangle with the two sides, so by the Pythagorean theorem d² = 12² + 5² = 144 + 25 = 169. Thus d = 13 cm.
Each term is obtained by multiplying the previous term by the common ratio 3. Therefore the next term is 135 × 3 = 405.
The equation log₂(32) = y means 2^y = 32. Since 2⁵ = 32, we get y = 5.
Let the numbers be a and b with a + b = 30 and a − b = 8. Adding the equations gives 2a = 38, so a = 19 and b = 30 − 19 = 11.
Circumference equals π times the diameter: C = πd = (22/7) × 14 = 44 cm.
Add 5 to both sides to get 4x ≥ 20, then divide both sides by the positive number 4, which keeps the inequality direction, giving x ≥ 5.
The probability the first ball is red is 5/12; given that, 4 red remain out of 11 balls, so the second is red with probability 4/11. Multiplying gives (5/12)(4/11) = 20/132 = 5/33.
Absolute value gives distance from zero, so |−13| = 13 and |−5| = 5. Subtracting gives 13 − 5 = 8.
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The third interior angle is 180° − 50° − 60° = 70°. The exterior angle is supplementary to it, so it equals 180° − 70° = 110°, which also equals the sum of the two remote interior angles.
The first term is a = 3 and the common ratio is r = 2. The nth term is a·r^(n−1), so the 8th term is 3 × 2⁷ = 3 × 128 = 384.
Substitute x = 3: f(3) = 3² + 4(3) − 2 = 9 + 12 − 2 = 19.
The volume of a cylinder is V = πr²h. Substituting r = 2 and h = 9 gives V = π(4)(9) = 36π cm³.
When multiplying powers with the same base, add the exponents: x⁵ · x³ = x⁸. When dividing, subtract the exponents: x⁸ / x⁶ = x².
In a right triangle, sin 30° = opposite / hypotenuse. Since sin 30° = 1/2, the opposite side is 10 × 1/2 = 5 cm, which also matches the 30-60-90 side ratio.
If the roots are positive integers with product 10, the possible pairs are (1, 10) and (2, 5). Since the sum of the roots equals −b and the sum must be positive, b = −(sum), giving b = −11 or b = −7. Of the listed choices, only −7 is possible.
Write both sides with base 2: 8^(x−1) = (2³)^(x−1) = 2^(3x−3). Equating exponents gives x + 1 = 3x − 3, so 4 = 2x and x = 2.
Total surface area of a cone is πr² + πrl. With r = 6 and l = 10, this is π(36) + π(60) = 96π cm².
A quadratic has exactly one real solution when its discriminant b² − 4ac equals zero. Here that means k² − 4(1)(9) = 0, so k² = 36 and k = ±6; among the choices, k = 6 works.
The nth term equals Sₙ − Sₙ₋₁. Here S₁₀ = 100 + 30 = 130 and S₉ = 81 + 27 = 108, so the 10th term is 130 − 108 = 22.