10x*x-15x-3.5=0

Solution for 10x*x-15x-3.5=0 equation:

10x*x-15x-3.5=0

We add all the numbers together, and all the variables

-15x+10x*x-3.5=0

Wy multiply elements

10x^2-15x-3.5=0

a = 10; b = -15; c = -3.5;
Δ = b2-4ac
Δ = -152-4·10·(-3.5)
Δ = 365
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{-(-15)-\sqrt{365}}{2*10}=\frac{15-\sqrt{365}}{20}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-15)+\sqrt{365}}{2*10}=\frac{15+\sqrt{365}}{20}
$