(300-x)x1/10=1890

Solution for (300-x)x1/10=1890 equation:

(300-x)x1/10=1890

We move all terms to the left:

(300-x)x1/10-(1890)=0

We add all the numbers together, and all the variables

(-1x+300)x1/10-1890=0

We multiply all the terms by the denominator


(-1x+300)x1-1890*10=0

We add all the numbers together, and all the variables

(-1x+300)x1-18900=0

We multiply parentheses

-1x^2+300x-18900=0

a = -1; b = 300; c = -18900;
Δ = b2-4ac
Δ = 3002-4·(-1)·(-18900)
Δ = 14400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{14400}=120$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(300)-120}{2*-1}=\frac{-420}{-2}
=+210
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(300)+120}{2*-1}=\frac{-180}{-2}
=+90
$