(0.25+x)*(0.15+x)-x=0

Solution for (0.25+x)*(0.15+x)-x=0 equation:

(0.25+x)(0.15+x)-x=0

We add all the numbers together, and all the variables

(x+0.25)(x+0.15)-x=0

We add all the numbers together, and all the variables

-1x+(x+0.25)(x+0.15)=0

We multiply parentheses ..

(+x^2+0.15x+0.25x+0.0375)-1x=0

We get rid of parentheses

x^2+0.15x+0.25x-1x+0.0375=0

We add all the numbers together, and all the variables

x^2-0.6x+0.0375=0

a = 1; b = -0.6; c = +0.0375;
Δ = b2-4ac
Δ = -0.62-4·1·0.0375
Δ = 0.21
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-0.6)-\sqrt{0.21}}{2*1}=\frac{0.6-\sqrt{0.21}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-0.6)+\sqrt{0.21}}{2*1}=\frac{0.6+\sqrt{0.21}}{2}
$