121/400=d^2

Solution for 121/400=d^2 equation:

121/400=d^2

We move all terms to the left:

121/400-(d^2)=0

We add all the numbers together, and all the variables

-1d^2+121/400=0

We multiply all the terms by the denominator


-1d^2*400+121=0

Wy multiply elements

-400d^2+121=0

a = -400; b = 0; c = +121;
Δ = b2-4ac
Δ = 02-4·(-400)·121
Δ = 193600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{193600}=440$
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-440}{2*-400}=\frac{-440}{-800}
=11/20
$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+440}{2*-400}=\frac{440}{-800}
=-11/20
$