25=(x+0.3)(x+0.3)

Solution for 25=(x+0.3)(x+0.3) equation:

25=(x+0.3)(x+0.3)

We move all terms to the left:

25-((x+0.3)(x+0.3))=0

We multiply parentheses ..

-((+x^2+0.3x+0.3x+0.09))+25=0


We calculate terms in parentheses: -((+x^2+0.3x+0.3x+0.09)), so:

(+x^2+0.3x+0.3x+0.09)

We get rid of parentheses

x^2+0.3x+0.3x+0.09

We add all the numbers together, and all the variables

x^2+0.6x+0.09

Back to the equation:

-(x^2+0.6x+0.09)


We get rid of parentheses

-x^2-0.6x-0.09+25=0

We add all the numbers together, and all the variables

-1x^2-0.6x+24.91=0

a = -1; b = -0.6; c = +24.91;
Δ = b2-4ac
Δ = -0.62-4·(-1)·24.91
Δ = 100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{100}=10$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-0.6)-10}{2*-1}=\frac{-9.4}{-2}
=4+1/1.4285714285714
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.6)+10}{2*-1}=\frac{10.6}{-2}
=-5+0.6/2
$