If C is between A and B, then, we can write the equation

Substitute the value of AB and the expressions for AC and CB in terms of x.

We can now solve for x.


Dividing by 5.








The number of bacteria in a culture is increasing according to the law of exponential growth. There are 125 bacteria in the culture after 2 hours and 350 bacteria after 4 hours.
Ggggggggg you want me to do that for one thing and she will it your you will your life mother of I
<h3>
Answer: choice C) 15</h3>
Simplify the left side to get
2(4+x)+(13+x)
2(4)+2(x) +13+x
8+2x+13+x
3x+21
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So the original equation
2(4+x)+(13+x) = 3x+k
turns into
3x+21 = 3x+k
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Subtract 3x from both sides
3x+21 = 3x+k
3x+21-3x = 3x+k-3x
21 = k
k = 21
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If k = 21, then the original equation will have infinitely many solutions. This is because we will end up with 3x+21 on both sides, leading to 0 = 0 after getting everything to one side. This is a true equation no matter what x happens to be.
If k is some fixed number other than 21, then there will be no solutions. This equation is inconsistent (one side says one thing, the other side says something different). If k = 15, then
3x+21 = 3x+k
3x+21 = 3x+15
21 = 15 .... subtract 3x from both sides
The last equation is false, so there are no solutions here.
note: if you replace k with a variable term, then there will be exactly one solution.