Answer:
78
Step-by-step explanation:
5^2 = 25 5^3 = 125 them two added together equals 150
6^2 = 36 so 36 plus 36 equals 72
150-72=78
Answer:
93
Step-by-step explanation:
Answer:
- 819
Step-by-step explanation:
The sum to n terms of a geometric series is
= 
where a is the first term and r the common ratio
Here a = 1 and r = - 4 ÷ 1 = - 4, thus
=
=
=
= - 819