5x^2-49=28x

Solution for 5x^2-49=28x equation:

5x^2-49=28x

We move all terms to the left:

5x^2-49-(28x)=0

a = 5; b = -28; c = -49;
Δ = b2-4ac
Δ = -282-4·5·(-49)
Δ = 1764
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1764}=42$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-28)-42}{2*5}=\frac{-14}{10}
=-1+2/5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-28)+42}{2*5}=\frac{70}{10}
=7
$