25x^2-9x-16=0

Solution for 25x^2-9x-16=0 equation:

25x^2-9x-16=0

a = 25; b = -9; c = -16;
Δ = b2-4ac
Δ = -92-4·25·(-16)
Δ = 1681
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1681}=41$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-9)-41}{2*25}=\frac{-32}{50}
=-16/25
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+41}{2*25}=\frac{50}{50}
=1
$