(3x-5)(6x-7.2)=0

Solution for (3x-5)(6x-7.2)=0 equation:

(3x-5)(6x-7.2)=0

We multiply parentheses ..

(+18x^2-21.6x-30x+36)=0

We get rid of parentheses

18x^2-21.6x-30x+36=0

We add all the numbers together, and all the variables

18x^2-51.6x+36=0

a = 18; b = -51.6; c = +36;
Δ = b2-4ac
Δ = -51.62-4·18·36
Δ = 70.56
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{-(-51.6)-\sqrt{70.56}}{2*18}=\frac{51.6-\sqrt{70.56}}{36}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-51.6)+\sqrt{70.56}}{2*18}=\frac{51.6+\sqrt{70.56}}{36}
$