(z+3)(z=4)=0

Solution for (z+3)(z=4)=0 equation:

(z+3)(z=4)=0

We move all terms to the left:

(z+3)(z-(4))=0

We multiply parentheses ..

(+z^2-4z+3z-12)=0

We get rid of parentheses

z^2-4z+3z-12=0

We add all the numbers together, and all the variables

z^2-1z-12=0

a = 1; b = -1; c = -12;
Δ = b2-4ac
Δ = -12-4·1·(-12)
Δ = 49
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{49}=7$
$z_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-1)-7}{2*1}=\frac{-6}{2}
=-3
$
$z_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1)+7}{2*1}=\frac{8}{2}
=4
$