9x2+39x+42=

Solution for 9x2+39x+42= equation:

9x^2+39x+42=

We move all terms to the left:

9x^2+39x+42-()=0

We add all the numbers together, and all the variables

9x^2+39x=0

a = 9; b = 39; c = 0;
Δ = b2-4ac
Δ = 392-4·9·0
Δ = 1521
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1521}=39$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(39)-39}{2*9}=\frac{-78}{18}
=-4+1/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(39)+39}{2*9}=\frac{0}{18}
=0
$