8. 29, 38, 47, 56, ...; 21st term

Tn=a+(n-1)d

Tn=29+(n-1)9

Tn=29+9n-9

Tn=20+9n

Tn=20+9 (21)

T21=580

Step-by-step explanation:

a=first term

d=common difference

Tn=a+(n-1)d general formula for an arithmetic number pattern

Step-by-step explanation:

I assume the 8 is the question number and the sequence is

29,38,47...

This is an arithmetic sequence as any term minus the previous term is a constant, called the common difference, which in this case is 47-38=38-29=9. An arithmetic sequence has the form

an=a+d(n-1)

Where an=nth term, a=initial term, d=common difference, and n=term number.

In this case a=29 and d=9 so

an=29+9(n-1)

an=9n+20, then the 21st term is

a(21)=9(21)+20

a(21)=189+20

a(21)=209

So the 21st term is 209.

1760 kilometers

step-by-step explanation:

multiply the amount of time the plane took to travel by it's speed

24 units

step-by-step explanation: