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what is the common ratio​

What Is The Common Ratio class=

Sagot :

Answer:

1. r = 3

Sn = a(r^n-1)

21 = 7(r^2-1)

21 = 7r

divide both sides by the 7 to remove the coefficient

3 = r

2. r = 1/2

Sn = a(r^n-1)

-1/4 = -1/2(r^2-1)

-1/4 = -1/2r

1/2 = r

3. r = 4

Sn = a(r^n-1)

-512 = -128(r^2-1)

-512 = -128r

4 = r