(X-3)(3x+10)=0

Solution for (X-3)(3x+10)=0 equation:

(X-3)(3X+10)=0

We multiply parentheses ..

(+3X^2+10X-9X-30)=0

We get rid of parentheses

3X^2+10X-9X-30=0

We add all the numbers together, and all the variables

3X^2+X-30=0

a = 3; b = 1; c = -30;
Δ = b2-4ac
Δ = 12-4·3·(-30)
Δ = 361
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{361}=19$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1)-19}{2*3}=\frac{-20}{6}
=-3+1/3
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+19}{2*3}=\frac{18}{6}
=3
$