Even number are of the form 2n. The sum of this sequence is the average of the first and last terms times the number of terms.
So the first term is 2 and the 25th term is 50 so the sum is:
(2+50)(25/2)
52*12.5=650
The conjecture they wish you to make is that for n terms, the sum will be:
s=n(n+1)
And for 25 terms that would give you:
s=25*26=650
Plug three in wherever there is an x
y=.25(3)
y=.75
The expression in scientific notation is given as follows:
3.5 x 10³.
<h3>What is scientific notation?</h3>
A number in scientific notation is given by:

With the base being
.
For this problem, the expression is given by:

When two factors of a multiplication have the same base and different exponent, we <u>keep the base and add the exponents,</u> hence:

5 x 4.2 = 21, hence the expression is:

When we divide two terms with the same base and different exponents, we keep the base and subtract the exponents, hence:

Which is the simplified expression.
More can be learned about scientific notation at brainly.com/question/16394306
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The simplified fraction is 62/7