We can write out a formula in order to solve this. Since sum represents addition, if x represents the unknown number, we can write the formula: x+51=-21. Then, to solve for x, you would subtract 51 from both sides to get x=-72 which is the final answer.
Answer:
21
Step-by-step explanation:
21-12=9
Answer: 5, 3,
, D
<u>Step-by-step explanation:</u>
-5 < 0 so f(-5) = | -5 | = 5
-3 < 0 so f(-3) = | -3 | = 3
6 > 0 so f(6) = 
graph D <em>(since x can equal zero)</em>
No, -8 - 2(3 + 2n) + 7n is not equivalent to -30 - 13n
Step-by-step explanation:
Let us revise the operation of the negative and positive numbers
- (-) + (-) = (-)
- (-) × (-) = (+)
- (-) + (+) = the sign of greatest [(-) if the greatest is (-) or (+) if the greatest is (+)]
- (-) × (+) = (-)
- (-) - (+) = (-)
- (+) - (-) = (+)
∵ The expression is -8 - 2(3 + 2n) + 7n
- Simplify it
∵ 2(3 + 2n) = 2(3) + 2(2n) = 6 + 4n
∴ -8 - 2(3 + 2n) + 7n = -8 - (6 + 4n) + 7n
- Multiply the bracket by (-)
∴ -8 - (6 + 4n) + 7n = -8 - 6 - 4n + 7n
- Add the like terms
∴ -8 - (6 + 4n) + 7n = (-8 - 6) - 4n + 7n
∴ -8 - (6 + 4n) + 7n = -14 + 3n
∴ -8 - 2(3 + 2n) + 7n is equivalent to -14 + 3n
∵ -14 + 3n ≠ -30 - 13n
∴ -8 - 2(3 + 2n) + 7n is not equivalent to -30 - 13n
No, -8 - 2(3 + 2n) + 7n is not equivalent to -30 - 13n
Learn more:
You can learn more about the directed numbers in brainly.com/question/10364988
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