WILL MARK BRAINLIEST 1. If a4 = -320 and r= -4 find a1
2. If a1= 3645 and a6 =15 find a3
3. Given the geometric sequence find s8 (3,-12,48,-192...)
4. Given the geometric sequence find s25 (1,5/3,7/3,3,11/3...)

a

step-by-step explanation:

strong negative correlation

let's call the solutions x₁ = (5 - 2√7)/3 and x₂ = (5 + 2√7)/3

then the equation is (x-x₁)(x-x₂) = 0

if you fill that in you get a lot of numbers which you can recognize as ax²+bx+c=0.

step-by-step explanation:

you can see that a=1 (there is just an x²)

b = (-5 -2√7 + 2√7 - 5)/3 = -10/3

c = -2√7)/3 ) * (-5+2√7)/3) = -1/3

so your answer is 3x^2 – 10x – 1 = 0