3x(x-10)=4

Solution for 3x(x-10)=4 equation:

3x(x-10)=4

We move all terms to the left:

3x(x-10)-(4)=0

We multiply parentheses

3x^2-30x-4=0

a = 3; b = -30; c = -4;
Δ = b2-4ac
Δ = -302-4·3·(-4)
Δ = 948
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{948}=\sqrt{4*237}=\sqrt{4}*\sqrt{237}=2\sqrt{237}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-2\sqrt{237}}{2*3}=\frac{30-2\sqrt{237}}{6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+2\sqrt{237}}{2*3}=\frac{30+2\sqrt{237}}{6}
$