(13x+26)(2,5-0,5x)=0

Solution for (13x+26)(2,5-0,5x)=0 equation:

(13x+26)(2.5-0.5x)=0

We add all the numbers together, and all the variables

(13x+26)(-0.5x+2.5)=0

We multiply parentheses ..

(+0x^2+32.5x+0x+65)=0

We get rid of parentheses

0x^2+32.5x+0x+65=0

We add all the numbers together, and all the variables

x^2+33.5x+65=0

a = 1; b = 33.5; c = +65;
Δ = b2-4ac
Δ = 33.52-4·1·65
Δ = 862.25
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{-(33.5)-\sqrt{862.25}}{2*1}=\frac{-33.5-\sqrt{862.25}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(33.5)+\sqrt{862.25}}{2*1}=\frac{-33.5+\sqrt{862.25}}{2}
$