2(g-10)g=g-20

Solution for 2(g-10)g=g-20 equation:

2(g-10)g=g-20

We move all terms to the left:

2(g-10)g-(g-20)=0

We multiply parentheses

2g^2-20g-(g-20)=0

We get rid of parentheses

2g^2-20g-g+20=0

We add all the numbers together, and all the variables

2g^2-21g+20=0

a = 2; b = -21; c = +20;
Δ = b2-4ac
Δ = -212-4·2·20
Δ = 281
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$g_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$g_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$g_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-21)-\sqrt{281}}{2*2}=\frac{21-\sqrt{281}}{4}
$
$g_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-21)+\sqrt{281}}{2*2}=\frac{21+\sqrt{281}}{4}
$