9m^2-15m-14=0

Solution for 9m^2-15m-14=0 equation:

9m^2-15m-14=0

a = 9; b = -15; c = -14;
Δ = b2-4ac
Δ = -152-4·9·(-14)
Δ = 729
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{729}=27$
$m_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-15)-27}{2*9}=\frac{-12}{18}
=-2/3
$
$m_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-15)+27}{2*9}=\frac{42}{18}
=2+1/3
$