0=0.3x^2+4x-70

Solution for 0=0.3x^2+4x-70 equation:

0=0.3x^2+4x-70

We move all terms to the left:

0-(0.3x^2+4x-70)=0

We add all the numbers together, and all the variables

-(0.3x^2+4x-70)=0

We get rid of parentheses

-0.3x^2-4x+70=0

a = -0.3; b = -4; c = +70;
Δ = b2-4ac
Δ = -42-4·(-0.3)·70
Δ = 100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{100}=10$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-4)-10}{2*-0.3}=\frac{-6}{-0.6}
=+10
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-4)+10}{2*-0.3}=\frac{14}{-0.6}
=-23+0.2/0.6
$