X(25x-31)=1680

Solution for X(25x-31)=1680 equation:

X(25X-31)=1680

We move all terms to the left:

X(25X-31)-(1680)=0

We multiply parentheses

25X^2-31X-1680=0

a = 25; b = -31; c = -1680;
Δ = b2-4ac
Δ = -312-4·25·(-1680)
Δ = 168961
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{-(-31)-\sqrt{168961}}{2*25}=\frac{31-\sqrt{168961}}{50}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-31)+\sqrt{168961}}{2*25}=\frac{31+\sqrt{168961}}{50}
$