-3x2-27x=42

Solution for -3x2-27x=42 equation:

-3x^2-27x=42

We move all terms to the left:

-3x^2-27x-(42)=0

a = -3; b = -27; c = -42;
Δ = b2-4ac
Δ = -272-4·(-3)·(-42)
Δ = 225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{225}=15$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-27)-15}{2*-3}=\frac{12}{-6}
=-2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-27)+15}{2*-3}=\frac{42}{-6}
=-7
$