2x(9x-4.5)=7,2

Solution for 2x(9x-4.5)=7,2 equation:

2x(9x-4.5)=7.2

We move all terms to the left:

2x(9x-4.5)-(7.2)=0

We add all the numbers together, and all the variables

2x(9x-4.5)-7.2=0

We multiply parentheses

18x^2-9x-7.2=0

a = 18; b = -9; c = -7.2;
Δ = b2-4ac
Δ = -92-4·18·(-7.2)
Δ = 599.4
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{-(-9)-\sqrt{599.4}}{2*18}=\frac{9-\sqrt{599.4}}{36}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+\sqrt{599.4}}{2*18}=\frac{9+\sqrt{599.4}}{36}
$