20m(m+1)=m-3

Solution for 20m(m+1)=m-3 equation:

20m(m+1)=m-3

We move all terms to the left:

20m(m+1)-(m-3)=0

We multiply parentheses

20m^2+20m-(m-3)=0

We get rid of parentheses

20m^2+20m-m+3=0

We add all the numbers together, and all the variables

20m^2+19m+3=0

a = 20; b = 19; c = +3;
Δ = b2-4ac
Δ = 192-4·20·3
Δ = 121
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{121}=11$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(19)-11}{2*20}=\frac{-30}{40}
=-3/4
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(19)+11}{2*20}=\frac{-8}{40}
=-1/5
$