The intrest of 15000for 4 years is 8100. what is the rate percent per annum

Step-by-step explanation:

this is an exemple

For instance, a 5% per annum interest rate on a loan worth $10,000 would cost $500. A per annum interest rate can be applied only to a principal loan amount.

b.-4 units

all you   do is count how many times you move

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