Help me PLEASE! will mark brainliest and also the other things
THX :)

for A    n=6

for B    x= 3.5

Step-by-step explanation:

A. so if you know what one thing is (10)then you sub them 28-10=18 now do 18/3 which is 6

b. same think but you do 7/2 which is 3.5

HOPE THIS HELPED :)

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