0=x^2-28x+147

Solution for 0=x^2-28x+147 equation:

0=x^2-28x+147

We move all terms to the left:

0-(x^2-28x+147)=0

We add all the numbers together, and all the variables

-(x^2-28x+147)=0

We get rid of parentheses

-x^2+28x-147=0

We add all the numbers together, and all the variables

-1x^2+28x-147=0

a = -1; b = 28; c = -147;
Δ = b2-4ac
Δ = 282-4·(-1)·(-147)
Δ = 196
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{196}=14$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(28)-14}{2*-1}=\frac{-42}{-2}
=+21
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(28)+14}{2*-1}=\frac{-14}{-2}
=+7
$