7x2=25x+12

Solution for 7x2=25x+12 equation:

7x^2=25x+12

We move all terms to the left:

7x^2-(25x+12)=0

We get rid of parentheses

7x^2-25x-12=0

a = 7; b = -25; c = -12;
Δ = b2-4ac
Δ = -252-4·7·(-12)
Δ = 961
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{961}=31$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-25)-31}{2*7}=\frac{-6}{14}
=-3/7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-25)+31}{2*7}=\frac{56}{14}
=4
$