Answer:
5th example: 28 blocks.
24th example: 123 blocks.
Step-by-step explanation:
Hope this helped!
The sum of the first n terms in a geometric sequence given the first term (a1) and the common ratio (r) is calculated through the equation,
<span>Sn </span>= (<span><span><span>a1</span>(1−<span>r^n</span>) / (</span><span>1−r)
Substituting the known terms,
Sn = (20)(1 - (1/4)^4)) / (1 - 1/4)
Sn = 26.5625
Thus, the sum of the first four terms is 26.5625. </span></span>
Answer:
(2x - 9)(2x + 9)
Step-by-step explanation:
4x^2 - 81 = (2x - 9)(2x + 9)
Is there any more of the problem