7x^2-45x=28=0

Solution for 7x^2-45x=28=0 equation:

7x^2-45x=28=0

We move all terms to the left:

7x^2-45x-(28)=0

a = 7; b = -45; c = -28;
Δ = b2-4ac
Δ = -452-4·7·(-28)
Δ = 2809
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2809}=53$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-45)-53}{2*7}=\frac{-8}{14}
=-4/7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-45)+53}{2*7}=\frac{98}{14}
=7
$