2x*(x-3)=(x*x)*1.25

Solution for 2x*(x-3)=(x*x)*1.25 equation:

2x(x-3)=(x*x)*1.25

We move all terms to the left:

2x(x-3)-((x*x)*1.25)=0

We add all the numbers together, and all the variables

2x(x-3)-((+x*x)*1.25)=0

We multiply parentheses

2x^2-6x-((+x*x)*1.25)=0


We calculate terms in parentheses: -((+x*x)*1.25), so:

(+x*x)*1.25

We multiply parentheses

1.25x^2

Back to the equation:

-(1.25x^2)


We get rid of parentheses

2x^2-1.25x^2-6x=0

We add all the numbers together, and all the variables

0.75x^2-6x=0

a = 0.75; b = -6; c = 0;
Δ = b2-4ac
Δ = -62-4·0.75·0
Δ = 36
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{36}=6$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-6)-6}{2*0.75}=\frac{0}{1.5}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-6)+6}{2*0.75}=\frac{12}{1.5}
=8
$