3x(x+5)=-4x+8

Solution for 3x(x+5)=-4x+8 equation:

3x(x+5)=-4x+8

We move all terms to the left:

3x(x+5)-(-4x+8)=0

We multiply parentheses

3x^2+15x-(-4x+8)=0

We get rid of parentheses

3x^2+15x+4x-8=0

We add all the numbers together, and all the variables

3x^2+19x-8=0

a = 3; b = 19; c = -8;
Δ = b2-4ac
Δ = 192-4·3·(-8)
Δ = 457
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{-(19)-\sqrt{457}}{2*3}=\frac{-19-\sqrt{457}}{6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(19)+\sqrt{457}}{2*3}=\frac{-19+\sqrt{457}}{6}
$