345=25x(5x+9)

Solution for 345=25x(5x+9) equation:

345=25x(5x+9)

We move all terms to the left:

345-(25x(5x+9))=0


We calculate terms in parentheses: -(25x(5x+9)), so:

25x(5x+9)

We multiply parentheses

125x^2+225x

Back to the equation:

-(125x^2+225x)


We get rid of parentheses

-125x^2-225x+345=0

a = -125; b = -225; c = +345;
Δ = b2-4ac
Δ = -2252-4·(-125)·345
Δ = 223125
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{223125}=\sqrt{625*357}=\sqrt{625}*\sqrt{357}=25\sqrt{357}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-225)-25\sqrt{357}}{2*-125}=\frac{225-25\sqrt{357}}{-250}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-225)+25\sqrt{357}}{2*-125}=\frac{225+25\sqrt{357}}{-250}
$