171x+756+9x2=0.

Solution for 171x+756+9x2=0. equation:

171x+756+9x^2=0.

a = 9; b = 171; c = +756;
Δ = b2-4ac
Δ = 1712-4·9·756
Δ = 2025
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2025}=45$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(171)-45}{2*9}=\frac{-216}{18}
=-12
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(171)+45}{2*9}=\frac{-126}{18}
=-7
$