50=r2-r1*2*1

Solution for 50=r2-r1*2*1 equation:

50=r2-r1*2*1

We move all terms to the left:

50-(r2-r1*2*1)=0

We add all the numbers together, and all the variables

-(+r^2-r1*2*1)+50=0

We get rid of parentheses

-r^2+r1*2*1+50=0

We add all the numbers together, and all the variables

-1r^2+r1*2*1+50=0

Wy multiply elements

-1r^2+2r*1+50=0

Wy multiply elements

-1r^2+2r+50=0

a = -1; b = 2; c = +50;
Δ = b2-4ac
Δ = 22-4·(-1)·50
Δ = 204
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{204}=\sqrt{4*51}=\sqrt{4}*\sqrt{51}=2\sqrt{51}$
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2)-2\sqrt{51}}{2*-1}=\frac{-2-2\sqrt{51}}{-2}
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+2\sqrt{51}}{2*-1}=\frac{-2+2\sqrt{51}}{-2}
$