(7x+5)(6x-4)=0

Solution for (7x+5)(6x-4)=0 equation:

(7x+5)(6x-4)=0

We multiply parentheses ..

(+42x^2-28x+30x-20)=0

We get rid of parentheses

42x^2-28x+30x-20=0

We add all the numbers together, and all the variables

42x^2+2x-20=0

a = 42; b = 2; c = -20;
Δ = b2-4ac
Δ = 22-4·42·(-20)
Δ = 3364
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3364}=58$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2)-58}{2*42}=\frac{-60}{84}
=-5/7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+58}{2*42}=\frac{56}{84}
=2/3
$