Answer:
90
Step-by-step explanation:
To find s4 we find sum of values when n=1,n=2,n=3,n=4
given expression is 
n=1 , plug in 1 for n

n=2

n=3

n=4

Sum of all 4 terms = 6+12+24+48=90
<u>Answer:</u>
<u>Step-by-step explanation:</u>
<u>We know that:</u>
<u>Surface area is the area of the faces of the cuboid.</u>
<u>Work:</u>
- => 2(7 x 4) + 2(5 x 4) + 2(5 x 7)
- => 2(28) + 2(20) + 2(35)
- => 56 + 40 + 70
- => 166 units²
Hence, <u>Option C is correct.</u>
Hoped this helped.

Yes. As long as it is linear, it will be continuous no matter the numbers. Now, I have no idea what a "real" number is, but I hope this helped.