(2a+4)(3a-7)=0

Solution for (2a+4)(3a-7)=0 equation:

(2a+4)(3a-7)=0

We multiply parentheses ..

(+6a^2-14a+12a-28)=0

We get rid of parentheses

6a^2-14a+12a-28=0

We add all the numbers together, and all the variables

6a^2-2a-28=0

a = 6; b = -2; c = -28;
Δ = b2-4ac
Δ = -22-4·6·(-28)
Δ = 676
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{676}=26$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-2)-26}{2*6}=\frac{-24}{12}
=-2
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2)+26}{2*6}=\frac{28}{12}
=2+1/3
$