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

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

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

We add all the numbers together, and all the variables

(5x-4)(-2x-3)=0

We multiply parentheses ..

(-10x^2-15x+8x+12)=0

We get rid of parentheses

-10x^2-15x+8x+12=0

We add all the numbers together, and all the variables

-10x^2-7x+12=0

a = -10; b = -7; c = +12;
Δ = b2-4ac
Δ = -72-4·(-10)·12
Δ = 529
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{529}=23$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-7)-23}{2*-10}=\frac{-16}{-20}
=4/5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-7)+23}{2*-10}=\frac{30}{-20}
=-1+1/2
$