(7w+5)(-w-3)=0

Solution for (7w+5)(-w-3)=0 equation:

(7w+5)(-w-3)=0

We add all the numbers together, and all the variables

(7w+5)(-1w-3)=0

We multiply parentheses ..

(-7w^2-21w-5w-15)=0

We get rid of parentheses

-7w^2-21w-5w-15=0

We add all the numbers together, and all the variables

-7w^2-26w-15=0

a = -7; b = -26; c = -15;
Δ = b2-4ac
Δ = -262-4·(-7)·(-15)
Δ = 256
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{256}=16$
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-26)-16}{2*-7}=\frac{10}{-14}
=-5/7
$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-26)+16}{2*-7}=\frac{42}{-14}
=-3
$