-7a^2-47a-30=0

Solution for -7a^2-47a-30=0 equation:

-7a^2-47a-30=0

a = -7; b = -47; c = -30;
Δ = b2-4ac
Δ = -472-4·(-7)·(-30)
Δ = 1369
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1369}=37$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-47)-37}{2*-7}=\frac{10}{-14}
=-5/7
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-47)+37}{2*-7}=\frac{84}{-14}
=-6
$