(3-7i)(7-7i)=0

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

(3-7i)(7-7i)=0

We add all the numbers together, and all the variables

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

We multiply parentheses ..

(+49i^2-49i-21i+21)=0

We get rid of parentheses

49i^2-49i-21i+21=0

We add all the numbers together, and all the variables

49i^2-70i+21=0

a = 49; b = -70; c = +21;
Δ = b2-4ac
Δ = -702-4·49·21
Δ = 784
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$i_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$i_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{784}=28$
$i_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-70)-28}{2*49}=\frac{42}{98}
=3/7
$
$i_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-70)+28}{2*49}=\frac{98}{98}
=1
$