0=3x^2+25x+28

Solution for 0=3x^2+25x+28 equation:

0=3x^2+25x+28

We move all terms to the left:

0-(3x^2+25x+28)=0

We add all the numbers together, and all the variables

-(3x^2+25x+28)=0

We get rid of parentheses

-3x^2-25x-28=0

a = -3; b = -25; c = -28;
Δ = b2-4ac
Δ = -252-4·(-3)·(-28)
Δ = 289
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{289}=17$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-25)-17}{2*-3}=\frac{8}{-6}
=-1+1/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-25)+17}{2*-3}=\frac{42}{-6}
=-7
$