x(x+3)=1,200

Solution for x(x+3)=1,200 equation:

x(x+3)=1.200

We move all terms to the left:

x(x+3)-(1.200)=0

We add all the numbers together, and all the variables

x(x+3)-(1.2)=0

We add all the numbers together, and all the variables

x(x+3)-1.2=0

We multiply parentheses

x^2+3x-1.2=0

a = 1; b = 3; c = -1.2;
Δ = b2-4ac
Δ = 32-4·1·(-1.2)
Δ = 13.8
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{-(3)-\sqrt{13.8}}{2*1}=\frac{-3-\sqrt{13.8}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(3)+\sqrt{13.8}}{2*1}=\frac{-3+\sqrt{13.8}}{2}
$