The answer for the question would’ve been 90
A(n)=4+4(n-1)
a(n)=4+4n-4
a(n)=4n
76=4n
n=19
The sum of any arithmetic sequence (series are infinite) is:
(a+a(n))(n/2)
The average of the first and last terms times the number of terms, in this case we found that n=19 so:
19(4+76)/2=760
78 is the answer
If you substract 914-836 that equals 78
And if you substract 836-758=78 too
3n-5=7
The three times a number goes first because there is the “less than” phrase.
Y- mx+c
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