Answer:
7x2 + 4 x + 20
Step-by-step explanation:
Subtract 3x2 from 10x2.7x2+10x+20−6xSubtract 6x from 10x.7x2+4x+20
Hello,
4 is to 78 as x is to 100, we write it as a ratio:
1) Negative five
-5 x 4 = -20
2) Negative eighty
-80 / -4 = 20
3) Negative 1/5
(-1/5) x (-20) = 4
4) Negative eighty
(-80) / 4 = -20
<h2>
Hello!</h2>
The answer is: 23.77 hours
<h2>
Why?</h2>

Where:
Total(t) is equal to the amount for a determined time (in hours)
<em>Start</em> is the original amount
<em>t </em>is the time in hours.
For example, it's known from the statement that the bacteria double their population every 15 hours, so it can be written like this:

To calculate how long it takes for the bacteria cells to increase to 300, we should do the following calculation:

So, to know if we are right, let's replace 23.77 h in the equation:
Total(t)=100*2^\frac{23.77}{15}=299.94
and 299.94≅300
Have a nice day!