Start by combing like terms. You will get 3x+12=51. Now subtract 12 from both sides (3x=39). Divide both sides by 3 (x=13). The answer is 13.
Answer:
Karen has to at least spend 11 minutes.
Step-by-step explanation:
This is because 57 - 13 = 44. 44 divided by 4 = 11. This means that in 11 minutes Karen will have a 57 liter tank. But she could keep going, but the least number of minutes would be 11 minutes, to get to 57 liters.
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Answer:

Step-by-step explanation:
3/8 + 1/4 + 1/2 - 2/3
- > 1/4 = 2/8
3/8 + 2/8 + 1/2 - 2/3
5/8 + 1/2 - 2/3
- > 1/2 = 4/8
5/8 + 4/8 - 2/3
9/8 - 2/3
- > LCM of 8,3: 24
- > 9/8 = 27/24
- > 2/3 = 16/24
27/24 - 16/24
11/24
Hope this helps you.
The answer is Associative