For each of the following, decide if the given series is a geometric series. A. 10 x4 + 11 x5 + 12 x6 + 13 x7 + Solution a. 11x^5/10x^4=11x/10 12x^6/11x^5=12x/11 both are not equal hence this is not a ageometric series B) 10x^5/10x^4=x 10x^6/10x^5=x equal so a geometric series first term a= 10x^4 ratio=r=x c. 100x/10=10x 1000x^2/100x=10x equal a=10 r=10x.