(-7d-2)(-5d-5)=0

Solution for (-7d-2)(-5d-5)=0 equation:

(-7d-2)(-5d-5)=0

We multiply parentheses ..

(+35d^2+35d+10d+10)=0

We get rid of parentheses

35d^2+35d+10d+10=0

We add all the numbers together, and all the variables

35d^2+45d+10=0

a = 35; b = 45; c = +10;
Δ = b2-4ac
Δ = 452-4·35·10
Δ = 625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{625}=25$
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(45)-25}{2*35}=\frac{-70}{70}
=-1
$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(45)+25}{2*35}=\frac{-20}{70}
=-2/7
$