260=3x^2+9x+50

Solution for 260=3x^2+9x+50 equation:

260=3x^2+9x+50

We move all terms to the left:

260-(3x^2+9x+50)=0

We get rid of parentheses

-3x^2-9x-50+260=0

We add all the numbers together, and all the variables

-3x^2-9x+210=0

a = -3; b = -9; c = +210;
Δ = b2-4ac
Δ = -92-4·(-3)·210
Δ = 2601
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2601}=51$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-9)-51}{2*-3}=\frac{-42}{-6}
=+7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+51}{2*-3}=\frac{60}{-6}
=-10
$