-9x^2+10x+4=0

Solution for -9x^2+10x+4=0 equation:

-9x^2+10x+4=0

a = -9; b = 10; c = +4;
Δ = b2-4ac
Δ = 102-4·(-9)·4
Δ = 244
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{244}=\sqrt{4*61}=\sqrt{4}*\sqrt{61}=2\sqrt{61}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(10)-2\sqrt{61}}{2*-9}=\frac{-10-2\sqrt{61}}{-18}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(10)+2\sqrt{61}}{2*-9}=\frac{-10+2\sqrt{61}}{-18}
$