21z(15z+10)=-

Solution for 21z(15z+10)=- equation:

21z(15z+10)=-

We move all terms to the left:

21z(15z+10)-(-)=0

We add all the numbers together, and all the variables

21z(15z+10)-0=0

We add all the numbers together, and all the variables

21z(15z+10)=0

We multiply parentheses

315z^2+210z=0

a = 315; b = 210; c = 0;
Δ = b2-4ac
Δ = 2102-4·315·0
Δ = 44100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{44100}=210$
$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(210)-210}{2*315}=\frac{-420}{630}
=-2/3
$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(210)+210}{2*315}=\frac{0}{630}
=0
$