(-4y-5)(-7y-1)=0

Solution for (-4y-5)(-7y-1)=0 equation:

(-4y-5)(-7y-1)=0

We multiply parentheses ..

(+28y^2+4y+35y+5)=0

We get rid of parentheses

28y^2+4y+35y+5=0

We add all the numbers together, and all the variables

28y^2+39y+5=0

a = 28; b = 39; c = +5;
Δ = b2-4ac
Δ = 392-4·28·5
Δ = 961
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{961}=31$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(39)-31}{2*28}=\frac{-70}{56}
=-1+1/4
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(39)+31}{2*28}=\frac{-8}{56}
=-1/7
$