What is the value of -7 + 12 - 5?
- -10
- 0 Correct answer.
- 10
- -24
Explanation
Work from left to right: -7 + 12 = 5, and then 5 - 5 = 0. Subtracting a positive number is the same as adding its opposite, so the final step moves 5 units left from 5.
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Work from left to right: -7 + 12 = 5, and then 5 - 5 = 0. Subtracting a positive number is the same as adding its opposite, so the final step moves 5 units left from 5.
Absolute value gives the distance from zero, so |-15| = 15 and |6| = 6. Subtracting gives 15 - 6 = 9.
Exponents come first: 3^2 = 9. Then multiply: 2 x 9 = 18, so the expression is 20 - 18 + 4, which equals 6.
The greatest common factor of 18 and 24 is 6. Dividing numerator and denominator by 6 gives 18/6 = 3 and 24/6 = 4, so the simplest form is 3/4.
Reading to the right of the decimal point, the first digit is tenths, the second is hundredths, and the third is thousandths. In 4.072 the 0 is tenths, the 7 is hundredths, and the 2 is thousandths.
A square root is a number that gives the radicand when multiplied by itself. Since 12 x 12 = 144, the square root of 144 is 12.
A whole number is divisible by 3 exactly when the sum of its digits is a multiple of 3. For 834 the digit sum is 8 + 3 + 4 = 15, and 15 is a multiple of 3, so 834 is divisible by 3.
Line up the decimal points and write 3.6 as 3.60. Adding 3.60 + 0.47 gives 4.07, with hundredths 0 + 7, tenths 6 + 4 = 10 (write 0, carry 1), and ones 3 + 0 + 1 = 4.
Both numbers factor as 36 = 2^2 x 3^2 and 48 = 2^4 x 3. Taking the lowest power of each shared prime gives 2^2 x 3 = 12.
Multiples of 12 are 12, 24, 36, ... and multiples of 8 are 8, 16, 24, ... The first value appearing in both lists is 24, so the least common multiple is 24.
Dividing by a fraction is the same as multiplying by its reciprocal, so 3/4 divided by 2/5 equals 3/4 x 5/2. Multiplying across gives 15/8.
Convert the percent to a decimal and multiply: 0.15 x 80 = 12. Equivalently, 10% of 80 is 8 and 5% of 80 is 4, and 8 + 4 = 12.
Scientific notation writes a number as a factor between 1 and 10 times a power of 10. Moving the decimal point in 0.00042 four places to the right gives 4.2, so the exponent is -4.
When multiplying powers with the same base, keep the base and add the exponents: 2^3 x 2^4 = 2^(3+4) = 2^7. Checking, 8 x 16 = 128 = 2^7.
An irrational number cannot be written as a fraction of two integers. The square root of 7 is not a perfect square and its decimal form never terminates or repeats, so it is irrational.
A unit rate is found by dividing the total cost by the number of ounces: 3.60 divided by 12 = 0.30. So the cereal costs $0.30 per ounce.
Write each value as a decimal: -2/3 is about -0.667, -5/8 = -0.625, and the others are -0.7 and -0.65. Among negatives, the one closest to zero is greatest, which is -0.625, or -5/8.
The distributive property multiplies each term inside the parentheses by 6: 6 x 2x = 12x and 6 x (-5) = -30. The result is 12x - 30.
Divide by primes until only primes remain: 84 = 2 x 42 = 2 x 2 x 21 = 2 x 2 x 3 x 7. Grouping the repeated 2s gives 2^2 x 3 x 7.
Rising means adding to the position and diving means subtracting. Starting at -85, the rise gives -85 + 40 = -45, and the dive gives -45 - 25 = -70 meters.
A negative exponent takes the reciprocal of the base: (2/3)^-2 = (3/2)^2. Squaring gives 9/4.
Let x = 0.363636... Then 100x = 36.363636..., and subtracting gives 99x = 36. So x = 36/99, which simplifies by a factor of 9 to 4/11.
First subtract inside the parentheses: 3/4 - 1/2 = 3/4 - 2/4 = 1/4. Then divide by 1/8 by multiplying by its reciprocal: 1/4 x 8 = 2.
Multiply the coefficients and add the exponents: 3 x 4 = 12 and 5 + (-8) = -3, giving 12 x 10^-3. Rewriting 12 as 1.2 x 10^1 and combining exponents gives 1.2 x 10^-2.
Multiply the two multipliers: 1.20 x 0.80 = 0.96. The final price is 96% of the original, which is a 4% decrease.
The order of operations requires evaluating the parentheses first: 2 + 1 = 3. Multiplication comes before subtraction, so 3 × 3 = 9, and then 8 − 9 = -1.
Absolute value gives the distance from zero, so |−7| = 7. Simplify inside the second bars first: 3 − 9 = -6 and |−6| = 6, then add 7 + 6 = 13.
A fraction equals its numerator divided by its denominator, so divide 5 by 8. Since 8 × 0.625 = 5, the decimal is 0.625.
The thousandths digit is the third digit after the decimal point, which is 6 in 0.04672. The following digit is 7, so the thousandths digit rounds up from 6 to 7, giving 0.047.
Rewrite each fraction with the least common denominator 12: 8/12 + 9/12 − 2/12. Combining gives 15/12, which simplifies to 5/4.
Set up the proportion (9/4)/12 = x/20 and solve for x. The unit rate is 3/16 cup per cookie, and 20 × 3/16 = 15/4, which is 3 3/4 cups.
The successive discounts multiply: 80 × 0.75 = $60 after the first discount, then 60 × 0.90 = $54. The combined effect is a 32.5% reduction, not a 35% reduction.
A power raised to a power multiplies exponents, so (2^3)^2 = 2^6. Dividing powers with the same base subtracts exponents: 2^6 ÷ 2^4 = 2^2 = 4.
Multiply both numbers by 1000 to clear the decimals: 360 ÷ 4 = 90. Scaling both the dividend and divisor by the same power of ten leaves the quotient unchanged.
Since 7^2 = 49 and 8^2 = 64, and 50 is between 49 and 64, the square root of 50 is between 7 and 8. It is just slightly greater than 7.
A negative exponent of -4 moves the decimal point four places to the left. Moving the point in 3.07 four places left gives 0.000307.
An increase of 12% means the new value is 1.12 times the original, so solve 1.12x = 56. Dividing gives x = 50, and checking: 50 × 1.12 = 56.
First add inside the parentheses using the common denominator 12: 9/12 + 10/12 = 19/12. Dividing by 2/3 means multiplying by its reciprocal 3/2, so 19/12 × 3/2 = 57/24 = 19/8.
A negative number squared is positive, so (−3)^2 = 9. A negative number cubed is negative, so (−2)^3 = -8, and subtracting it gives 9 − (-8) = 9 + 8 = 17.
Divide the time by the fraction of the tank filled to get the time for one full tank: 9 ÷ 3/5 = 9 × 5/3 = 15 minutes. Two tanks then take 2 × 15 = 30 minutes.
Undo the addition first by subtracting 7 from both sides, which gives 3x = 15. Then divide both sides by 3 to isolate x, giving x = 5. Checking the result: 3(5) + 7 = 22 is true.
Slope equals the change in y divided by the change in x: (11 - 3)/(6 - 2). This simplifies to 8/4, which is 2. The slope is positive because y increases as x increases.
Substitute -2 for every x, remembering that (-2)² = 4: 2(4) - 3(-2) + 1. This becomes 8 + 6 + 1, which equals 15. The product -3(-2) is positive 6, not -6.
Distributing the 4 gives 8x - 12, so the expression becomes 8x - 12 - 5x. Combining like terms gives 3x - 12. Only the x-terms combine; the constant stays as -12.
Function notation means substitute -2 wherever x appears, giving 3(-2) - 5. This equals -6 - 5, which is -11. The negative input is preserved throughout the computation.
The y-intercept is found by setting x = 0, which gives 3y = 12, so y = 4. The intercept is the point (0, 4). Substituting x = 0 is the standard method for finding where a graph crosses the y-axis.
In -3² the exponent applies only to 3, so the value is -(3²) = -9. The cube of -2 is -8 because a negative base with an odd exponent stays negative. Adding gives -9 + (-8) = -17.
Direct variation means y = kx, so first find k = 12/3 = 4. Then y = 4(5) = 20. Direct variation requires finding the constant of proportionality before substituting the new value.
Subtract 5 from both sides to get -2x > 6. Dividing both sides by -2 reverses the direction of the inequality, giving x < -3. Reversing the symbol is required whenever you divide or multiply by a negative number.
Substituting y = 2x + 1 into the second equation gives 3x + 2x + 1 = 16, so 5x = 15 and x = 3. Then y = 2(3) + 1 = 7. The solution must satisfy both equations, and 3(3) + 7 = 16 confirms it.