There are ten bird baths in a park. On the first day of spring, the bird baths are filled. Several weeks later, the overall ch
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Answer:
Step-by-step explanation:
Factor it by first setting it equal to 0:
Now subtract 9 from both sides:
Divide both sides by 4:
Then take the square root of both sides:
x = ± , which of course is not allowed. Therefore, we have to allow for the imaginary numbers in this solution. Knowing that,
x = ± is an equivalent radicand, we can now replace -1 with its imaginary counterpart:
x = ±
Each one of the elements in the radicand are perfect squares, so we simplify as follows:
x = ±
And there you go!
Answer:
7 hours
Step-by-step explanation:
Since, the final amount of caffeine formula would be,
Where,
P = Initial value,
r = rate per period,
t = number of periods,
Here, r = 10% = 0.10, t = h, A =
Taking log both sides,
Hence, after 7 hours the amount of caffeine in a body to reduce by half.
Answer:
The price of one cookie is $1.25 and the price of one cake is $15.
Step-by-step explanation:
Let $x be the price of one cookie and $y be the price of one cake.
1. On Monday, Sean bought 3 cookies and 5 cakes, then he spent $(3x+5y) and this is $78.75. Thus,
2. On Tuesday, Sean bought 8 cookies and 2 cakes, then he spent $(8x+2y) and this is $40. Thus,
3. Solve the system of two equations:
Multiply the first equation by 2 and the second equation by 5 and subtract them:
Then