-6=-2(j+9)j=

Solution for -6=-2(j+9)j= equation:

-6=-2(j+9)j=

We move all terms to the left:

-6-(-2(j+9)j)=0


We calculate terms in parentheses: -(-2(j+9)j), so:

-2(j+9)j

We multiply parentheses

-2j^2-18j

Back to the equation:

-(-2j^2-18j)


We get rid of parentheses

2j^2+18j-6=0

a = 2; b = 18; c = -6;
Δ = b2-4ac
Δ = 182-4·2·(-6)
Δ = 372
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$j_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$j_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{372}=\sqrt{4*93}=\sqrt{4}*\sqrt{93}=2\sqrt{93}$
$j_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(18)-2\sqrt{93}}{2*2}=\frac{-18-2\sqrt{93}}{4}
$
$j_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(18)+2\sqrt{93}}{2*2}=\frac{-18+2\sqrt{93}}{4}
$