3(x^2-70x+1000)=0

Solution for 3(x^2-70x+1000)=0 equation:

3(x^2-70x+1000)=0

We multiply parentheses

3x^2-210x+3000=0

a = 3; b = -210; c = +3000;
Δ = b2-4ac
Δ = -2102-4·3·3000
Δ = 8100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{8100}=90$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-210)-90}{2*3}=\frac{120}{6}
=20
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-210)+90}{2*3}=\frac{300}{6}
=50
$