y^2+3y=279

Solution for y^2+3y=279 equation:

y^2+3y=279

We move all terms to the left:

y^2+3y-(279)=0

a = 1; b = 3; c = -279;
Δ = b2-4ac
Δ = 32-4·1·(-279)
Δ = 1125
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{1125}=\sqrt{225*5}=\sqrt{225}*\sqrt{5}=15\sqrt{5}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(3)-15\sqrt{5}}{2*1}=\frac{-3-15\sqrt{5}}{2}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3)+15\sqrt{5}}{2*1}=\frac{-3+15\sqrt{5}}{2}
$