Alright First you combine the like terms.
9n - 3n = 6n
21 - 24 = -3
Rewrite the simplified equation
6n - 3 = 0
Solve for n
6n = 3
n = 3/6
n = 1/2
Ask if you need more help! :)
Answer:
The correct option is C: the isotope of iodine contains 81 neutrons.
Step-by-step explanation:
The mass (A) of the iodine isotope is given by:

Where:
Z: is the number of protons
N: is the number of neutrons
For iodine Z= 53, so if A = 134 the number of neutrons is:

Therefore, the correct option is C. The isotope of iodine contains 81 neutrons.
I hope it helps you!
2/3 of the farmers land had been planted with pechay
Answer:
(-1)(-3)
Step-by-step explanation:
When two negatives are multiplied it always equals a positive making it the only one that equals positive 3.
Answer:
Step-by-step explanation:
If the first floor of the Willis Tower is 21 feet high. and each additional floor is 12 feet high, then the floor heights as we move from one floor to another we keep increasing by 12feets and forms an arithmetic progression as shown;
21, (21+12), (21+12+12), ...
<em>21, 33, 45...</em>
a) To write an equation for the nth floor of the tower, we will have to find the nth term of the sequence using the formula for finding the nth term of an arithmetic sequence.
The nth term of an arithmetic sequence is expressed as 
a is the first term = 21
d is the common difference = 33-21 = 45-33 = 12
n is the number of terms
Substituting the given parameters into the formula;

<em>Hence the equation for the nth floor of the tower is expressed as </em>
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b) To get the height of the 65th floor, we will substitute n = 65 into the formula arrived at in (a)

<em>Hence the height of the 65th floor is 789feets.</em>