4x(3x+40)=30

Solution for 4x(3x+40)=30 equation:

4x(3x+40)=30

We move all terms to the left:

4x(3x+40)-(30)=0

We multiply parentheses

12x^2+160x-30=0

a = 12; b = 160; c = -30;
Δ = b2-4ac
Δ = 1602-4·12·(-30)
Δ = 27040
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:

$\sqrt{\Delta}=\sqrt{27040}=\sqrt{2704*10}=\sqrt{2704}*\sqrt{10}=52\sqrt{10}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(160)-52\sqrt{10}}{2*12}=\frac{-160-52\sqrt{10}}{24}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(160)+52\sqrt{10}}{2*12}=\frac{-160+52\sqrt{10}}{24}
$