9/121=y^2

Solution for 9/121=y^2 equation:

9/121=y^2

We move all terms to the left:

9/121-(y^2)=0

We add all the numbers together, and all the variables

-1y^2+9/121=0

We multiply all the terms by the denominator


-1y^2*121+9=0

Wy multiply elements

-121y^2+9=0

a = -121; b = 0; c = +9;
Δ = b2-4ac
Δ = 02-4·(-121)·9
Δ = 4356
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4356}=66$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-66}{2*-121}=\frac{-66}{-242}
=3/11
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+66}{2*-121}=\frac{66}{-242}
=-3/11
$