Answer:
Step-by-step explanation:
The formula for area of a rectange is lw, where l is length and w is width. Since x-4 and 5x+2 are the sides, we can multiply them together to give us the area. We do (x-4)(5x+2). We use the FOIL method (First Outside Inside Last) and get 5x^2-18x-8.
The sum of the given series can be found by simplification of the number
of terms in the series.
Reasons:
The given sequence is presented as follows;
A = 1011 + 337 + 337/2 + 1011/10 + 337/5 + ... + 1/2021
Therefore;
The n + 1 th term of the sequence, 1, 3, 6, 10, 15, ..., 2021 is given as follows;
Therefore, for the last term we have;
2 × 2043231 = n² + 3·n + 2
Which gives;
n² + 3·n + 2 - 2 × 2043231 = n² + 3·n - 4086460 = 0
Which gives, the number of terms, n = 2020
Which gives;
Learn more about the sum of a series here: