Answer:
Tn = 2n+4
T20 = 44
Step-by-step explanation:
Given Sn = n²+ 5 n-6
Tn = Sn - Sn-1
Sn-1 = (n-1)² + 5(n-1) - 6
Tn = n²+ 5n-6 - ((n-1)² + 5(n-1) - 6))
Tn = n²+ 5n-6-(n²-2n+1+5n-5-6)
Tn = n²+ 5n-6-n²+2n-1-5n+5+6
Tn = 2n-7+11
Tn = 2n+4
Get the general term is 2n+4
To get the 20th term;
T20 = 2(20) + 4
T20 = 40+4
T20 = 44
Hence the 20th term of the sequence is 44
