0.9x2+5.4x-4=0

Solution for 0.9x2+5.4x-4=0 equation:

0.9x^2+5.4x-4=0

a = 0.9; b = 5.4; c = -4;
Δ = b2-4ac
Δ = 5.42-4·0.9·(-4)
Δ = 43.56
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5.4)-\sqrt{43.56}}{2*0.9}=\frac{-5.4-\sqrt{43.56}}{1.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5.4)+\sqrt{43.56}}{2*0.9}=\frac{-5.4+\sqrt{43.56}}{1.8}
$