X + y = 3
2 answers:
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Answer:
1. x+4x
2. 5x
3.
4. 4x-2x+15
5.
Step-by-step explanation:
To write expressions remember these key words:
- a number is a variable like x
- sum is +
- difference and subtracted is -
- quotient is ÷
- product is ×
- reciprocal means flip like
- square is an exponent of 2 like
1. x+4x
2. 5x
3.
Remember a quotient would be but the reciprocal is
.
4. 4x-2x+15
5.
Since the sum of the numbers on the three draws is 12, if we want the card numbered 2 to be drawn exactly two times, the third card can only be numbered 8. In fact, , and there are no other possibilities, unless you consider the various permutations of the terms.
So, we have three favourable cases: we can draw 2,2,8, or 2,8,2, or 8,2,2. This are the only three cases where the card numbered 2 is drawn exactly two times, and the sum of the number on the three draws is 12.
Now, the question is: we have three favourable cases over how many? Well, we have 5 possible outcomes with each draws, and the three draws are identical, because we replace the card we draw every time.
So, we have 5 possible outcomes for the first draw, 5 for the second and 5 for the third. This leads to a total of possible triplets.
Once we know the "good" cases and the total number of possible cases, the probability is simply computed as