3.5x^2-60x+200=0

Solution for 3.5x^2-60x+200=0 equation:

3.5x^2-60x+200=0

a = 3.5; b = -60; c = +200;
Δ = b2-4ac
Δ = -602-4·3.5·200
Δ = 800
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:

$\sqrt{\Delta}=\sqrt{800}=\sqrt{400*2}=\sqrt{400}*\sqrt{2}=20\sqrt{2}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-60)-20\sqrt{2}}{2*3.5}=\frac{60-20\sqrt{2}}{7}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-60)+20\sqrt{2}}{2*3.5}=\frac{60+20\sqrt{2}}{7}
$