-0.3x^2+2.7x+7=0

Solution for -0.3x^2+2.7x+7=0 equation:

-0.3x^2+2.7x+7=0

a = -0.3; b = 2.7; c = +7;
Δ = b2-4ac
Δ = 2.72-4·(-0.3)·7
Δ = 15.69
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{-(2.7)-\sqrt{15.69}}{2*-0.3}=\frac{-2.7-\sqrt{15.69}}{-0.6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2.7)+\sqrt{15.69}}{2*-0.3}=\frac{-2.7+\sqrt{15.69}}{-0.6}
$