Quadratic Equation Hidden, ax^2+bx+c=0

Hey all,

I need help with this equation. It is a hidden equation which I have tried to solve on my maths booklet.

The steps that must be followed are:

ax^2 + bx + c = 0

I have to use the quadratic formula and tranpose the above

here is my question

1 / R + R = 3 + 7 / R

I need to get the A , b , c and plug it in the quadratic formula but the issue is i don't get the right answer which is 4.37, I believe I get the wrong A , B , C values at the start.

If i need to be more specify please tell me.