(5d-7)(d-6)=0

Solution for (5d-7)(d-6)=0 equation:

(5d-7)(d-6)=0

We multiply parentheses ..

(+5d^2-30d-7d+42)=0

We get rid of parentheses

5d^2-30d-7d+42=0

We add all the numbers together, and all the variables

5d^2-37d+42=0

a = 5; b = -37; c = +42;
Δ = b2-4ac
Δ = -372-4·5·42
Δ = 529
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{529}=23$
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-37)-23}{2*5}=\frac{14}{10}
=1+2/5
$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-37)+23}{2*5}=\frac{60}{10}
=6
$