For the arithmetic sequence beginning with the terms (1, 4, 7, 10, 13, 16...),
what is the sum of the
first 19 terms?

T2-T1 => 4-1 => 3

So, Common Difference is ‘3’ = d

And,

Tn = a+(n-1)d [d=3,n=20(n’th term), a=1(first term)

T(20) = 1+(20-1)3 => 1+(19)3 => 1+57 => 58

Sn = n/2×(a+l) [l=last term]

S(20) = 20/2×(1+58) = 10×59 = 590

The answer is 55

Step-by-step explanation:

Add 3 each time

Step-by-step explanation:

f(x)=2/3x-8, which give g(x) the greatest value.

step-by-step explanation: