3.14*x^2+4*3.14*x-140=0

Solution for 3.14*x^2+4*3.14*x-140=0 equation:

3.14x^2+4*3.14x-140=0

Wy multiply elements

3.14x^2+12x-140=0

a = 3.14; b = 12; c = -140;
Δ = b2-4ac
Δ = 122-4·3.14·(-140)
Δ = 1902.4
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{-(12)-\sqrt{1902.4}}{2*3.14}=\frac{-12-\sqrt{1902.4}}{6.28}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12)+\sqrt{1902.4}}{2*3.14}=\frac{-12+\sqrt{1902.4}}{6.28}
$