(9+3i)(7-2i)=0

Solution for (9+3i)(7-2i)=0 equation:

(9+3i)(7-2i)=0

We add all the numbers together, and all the variables

(3i+9)(-2i+7)=0

We multiply parentheses ..

(-6i^2+21i-18i+63)=0

We get rid of parentheses

-6i^2+21i-18i+63=0

We add all the numbers together, and all the variables

-6i^2+3i+63=0

a = -6; b = 3; c = +63;
Δ = b2-4ac
Δ = 32-4·(-6)·63
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{-(3)-39}{2*-6}=\frac{-42}{-12}
=3+1/2
$
$i_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3)+39}{2*-6}=\frac{36}{-12}
=-3
$