3(x+4)5x-7=(-11)

Solution for 3(x+4)5x-7=(-11) equation:

3(x+4)5x-7=(-11)

We move all terms to the left:

3(x+4)5x-7-((-11))=0

We add all the numbers together, and all the variables

3(x+4)5x+4=0

We multiply parentheses

15x^2+60x+4=0

a = 15; b = 60; c = +4;
Δ = b2-4ac
Δ = 602-4·15·4
Δ = 3360
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:

$\sqrt{\Delta}=\sqrt{3360}=\sqrt{16*210}=\sqrt{16}*\sqrt{210}=4\sqrt{210}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(60)-4\sqrt{210}}{2*15}=\frac{-60-4\sqrt{210}}{30}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(60)+4\sqrt{210}}{2*15}=\frac{-60+4\sqrt{210}}{30}
$