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Aleks [24]
3 years ago
10

The sum of a number and 2 times the number is 21. Find the number.

Mathematics
2 answers:
sveta [45]3 years ago
6 0
To find the number you would start by writing out the equation using x as the number. The equation would be x+2x=21. The first step to solve this equation would be to combine like terms, making the equation 3x=21. Finally, you would divide both sides by three, making your answer x=7.
shutvik [7]3 years ago
5 0
2x + x = 21. Combine your like terms and you get3x = 21. Divide both by sides 3 and you get x = 21.
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sergij07 [2.7K]

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The number of gallons of water in the tank at t=10.5 is

... W(10.5) = 160,000 -10.5(8000 -10.5) = 76110.25

The rate of change over the interval is

... (W(10.5) - W(10))/(10.5 - 10) = (76110.25 - 80100)/(0.5) = -7979.5

The average rate of change in the number of gallons of water in the tank over the interval is -7979.5 gal/min.

The sign is negative, so the amount of water is decreasing.

3 0
3 years ago
When Albertina opened her law office, she bought $18,000 worth of law books and $7,300 worth of furniture. She paid $1,400 down
fredd [130]
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dem82 [27]

Step-by-step explanation:

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3 0
3 years ago
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melomori [17]

Answer:

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