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

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

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

We add all the numbers together, and all the variables

(-5i-2)(-2i+7)=0

We multiply parentheses ..

(+10i^2-35i+4i-14)=0

We get rid of parentheses

10i^2-35i+4i-14=0

We add all the numbers together, and all the variables

10i^2-31i-14=0

a = 10; b = -31; c = -14;
Δ = b2-4ac
Δ = -312-4·10·(-14)
Δ = 1521
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$i_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$i_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1521}=39$
$i_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-31)-39}{2*10}=\frac{-8}{20}
=-2/5
$
$i_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-31)+39}{2*10}=\frac{70}{20}
=3+1/2
$