The Answer: (-b + 15) (15 - b)
The half-life of the radioactive substance is 67.95 hours.
Answer:
Length: 21 cm and Width: 6cm
Step-by-step explanation:
Let
be the width and
length of the rectangle. We know:
-------- eq. 1
(Perimeter of the rectangle) ------- eq. 2
Substitute equation 1 in equation 2:

Using the value of y, we find x.

Answer:
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