30x^2+21x-36=0

Solution for 30x^2+21x-36=0 equation:

30x^2+21x-36=0

a = 30; b = 21; c = -36;
Δ = b2-4ac
Δ = 212-4·30·(-36)
Δ = 4761
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4761}=69$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(21)-69}{2*30}=\frac{-90}{60}
=-1+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(21)+69}{2*30}=\frac{48}{60}
=4/5
$