(4r^2)/9=25

Solution for (4r^2)/9=25 equation:

(4r^2)/9=25

We move all terms to the left:

(4r^2)/9-(25)=0

We multiply all the terms by the denominator


4r^2-25*9=0

We add all the numbers together, and all the variables

4r^2-225=0

a = 4; b = 0; c = -225;
Δ = b2-4ac
Δ = 02-4·4·(-225)
Δ = 3600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3600}=60$
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-60}{2*4}=\frac{-60}{8}
=-7+1/2
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+60}{2*4}=\frac{60}{8}
=7+1/2
$