(5x-4)(2x+6)=0

Solution for (5x-4)(2x+6)=0 equation:

(5x-4)(2x+6)=0

We multiply parentheses ..

(+10x^2+30x-8x-24)=0

We get rid of parentheses

10x^2+30x-8x-24=0

We add all the numbers together, and all the variables

10x^2+22x-24=0

a = 10; b = 22; c = -24;
Δ = b2-4ac
Δ = 222-4·10·(-24)
Δ = 1444
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1444}=38$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(22)-38}{2*10}=\frac{-60}{20}
=-3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(22)+38}{2*10}=\frac{16}{20}
=4/5
$