Sum of n terms of a geometric series is
Sn = a1 (r^n-1)/(r-1)
a1 = 1st term = 4
r = common ratio = 12/4 = 3
so, the sum is
Sn = 4 (3^n-1)/(3-1) = 2(3^n-1)
One irrational number between 5 and 7 is

.
Answer:
−8^4+2^3−4^2+6
Step-by-step explanation:
Distribute the - to 8x^4-5x^3+6x^2-2x:
-8x^4+5x^3-6x^2+2x
Now simplify:
-3x^3+2x^2+4x-8x^4+5x^3-6x^2+2x= −8^4+2^3−4^2+6
Hope this helps!