It has become somewhat fashionable to have students derive the Quadratic Formula themselves; this is done by completing the square for the generic quadratic equation ax2 + bx + c = 0. While I can understand the impulse (showing students how the Formula was invented, and thereby providing a concrete example of the usefulness of abstract symbolic manipulation), the computations involved are often a bit beyond the average student at this point.
Answer:

Step-by-step explanation:
we know that
In an <u><em>Arithmetic Sequence</em></u> the difference between one term and the next is a constant, called the common difference
The formula for an Arithmetic Sequence is equal to

where
d is the common difference
n is the number of terms
a_1 is the first term of the sequence
In this problem we have

substitute



so
<u><em>Find the first ten terms</em></u>

For n=2 ----> 
For n=3 ----> 
For n=4 ----> 
For n=5 ----> 
For n=6 ----> 
For n=7 ----> 
For n=8 ----> 
For n=9 ----> 
For n=10 ----> 
The sequence is

<em>Hi there!</em>
<em>This should be easy,lol!</em>
<em>Answer:</em>
<em />
<em> (Decimal: -221.702503)</em>
<em />
<em> (Decimal: 280.592231)</em>
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<em />
<em>Sorry bout the explanation thingy. Their really long -.-!</em>
<em>But the last one is short so i'll put it for you!</em>
<em>Step-by-step explanation:</em>
<em>∴!For the last one!∴</em>
<em />
<em />
<em>Simplifies to:</em>
<em />
<em />
<em />
<em> </em>
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<em>Have a great day/night!</em>
If the perimeter is 200 ft and the area is 2100 square feet...
P = 2l + 2w
A = l * w
The dimensions would be 30 ft by 70 ft.