2(7x+3)(4x+5)=0

Solution for 2(7x+3)(4x+5)=0 equation:

2(7x+3)(4x+5)=0

We multiply parentheses ..

2(+28x^2+35x+12x+15)=0

We multiply parentheses

56x^2+70x+24x+30=0

We add all the numbers together, and all the variables

56x^2+94x+30=0

a = 56; b = 94; c = +30;
Δ = b2-4ac
Δ = 942-4·56·30
Δ = 2116
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2116}=46$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(94)-46}{2*56}=\frac{-140}{112}
=-1+1/4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(94)+46}{2*56}=\frac{-48}{112}
=-3/7
$