(1x+3)(-2x-5)=0

Solution for (1x+3)(-2x-5)=0 equation:

(1x+3)(-2x-5)=0

We add all the numbers together, and all the variables

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

We multiply parentheses ..

(-2x^2-5x-6x-15)=0

We get rid of parentheses

-2x^2-5x-6x-15=0

We add all the numbers together, and all the variables

-2x^2-11x-15=0

a = -2; b = -11; c = -15;
Δ = b2-4ac
Δ = -112-4·(-2)·(-15)
Δ = 1
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1}=1$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-11)-1}{2*-2}=\frac{10}{-4}
=-2+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-11)+1}{2*-2}=\frac{12}{-4}
=-3
$