2x2+x=55

Solution for 2x2+x=55 equation:

2x^2+x=55

We move all terms to the left:

2x^2+x-(55)=0

a = 2; b = 1; c = -55;
Δ = b2-4ac
Δ = 12-4·2·(-55)
Δ = 441
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{441}=21$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1)-21}{2*2}=\frac{-22}{4}
=-5+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+21}{2*2}=\frac{20}{4}
=5
$