(2x-15)(4x+13)=0

Solution for (2x-15)(4x+13)=0 equation:

(2x-15)(4x+13)=0

We multiply parentheses ..

(+8x^2+26x-60x-195)=0

We get rid of parentheses

8x^2+26x-60x-195=0

We add all the numbers together, and all the variables

8x^2-34x-195=0

a = 8; b = -34; c = -195;
Δ = b2-4ac
Δ = -342-4·8·(-195)
Δ = 7396
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{7396}=86$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-34)-86}{2*8}=\frac{-52}{16}
=-3+1/4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-34)+86}{2*8}=\frac{120}{16}
=7+1/2
$