Question

Sum of infinite series is 57 and sum of their cubes is 9747

Answer 1

Answer:

a² = 171 ( r²+r+1 )

Step-by-step explanation:

a/1-r = 57

a³/1-r³ = 9747

a²/ r²+r+1 = 171

a² = 171 ( r²+r+1 )