7i(5-2i)=0

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

7i(5-2i)=0

We add all the numbers together, and all the variables

7i(-2i+5)=0

We multiply parentheses

-14i^2+35i=0

a = -14; b = 35; c = 0;
Δ = b2-4ac
Δ = 352-4·(-14)·0
Δ = 1225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$i_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$i_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1225}=35$
$i_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(35)-35}{2*-14}=\frac{-70}{-28}
=2+1/2
$
$i_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(35)+35}{2*-14}=\frac{0}{-28}
=0
$