9z2+30z+25=4

Solution for 9z2+30z+25=4 equation:

9z^2+30z+25=4

We move all terms to the left:

9z^2+30z+25-(4)=0

We add all the numbers together, and all the variables

9z^2+30z+21=0

a = 9; b = 30; c = +21;
Δ = b2-4ac
Δ = 302-4·9·21
Δ = 144
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{144}=12$
$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-12}{2*9}=\frac{-42}{18}
=-2+1/3
$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+12}{2*9}=\frac{-18}{18}
=-1
$