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Answer: Choice D</h3>
The plus/minus of the following: 1/2, 1, 2, 5/2, 4, 5, 10, 20
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Explanation:
Refer to the rational root theorem. To find the possible rational roots, we divide the factors of the last term 20 over the factors of the first coefficient 2.
- Factors of 20 are: 1,2,4,5,10,20
- Factors of 2 are: 1,2
Dividing those said factors leads us to the list in choice D. We include the positive and negative versions of each result. For example, divide 10 over 2 to get 10/2 = 5 as one possible root (which leads to -5 as well).
A table like the one shown below might be handy to keep track of all the terms.
Answer:

Step-by-step explanation:

Find common denominator for 13 and 39
common denominator is 39
rewrite fractions so they have the same denominator

add them up

simplify/ put in the lowest terms

Answer:
A.
Step-by-step explanation:
one x value cant go to two y values
Exponential decay formula is :
Where a≠0, b≠1 , b represent growth or decay factor (or rate) and x is any real number.
But if a radioactive isotope decays in half every year which means the decay factor or decay rate is 50% or
.
So, the formula for half decay will be:

Where
represent c) The rate of isotope decreases.