Question

1.CONSIDER AN ARITHMETIC SEQUENCE WHOSE 7TH TERM34 AND 15TH TERM IS 66.FIND THE 20T TERM.​

Answer 1

Answer:

86

Step-by-step explanation:

T7=a+(n-1)d;= a+6d=34; a=34-6d

(derivating this expression in T15 equation)

T15=66=a+14d;

=34-6d+14d;= 34+8d=66;

So; d=4

(now using this value to find 'a')

a=34-6d;= a=34-24 =10

So;

T20= a + 19d ;= 10 + 76

=86