42*42+40*40=c*c

Solution for 42*42+40*40=c*c equation:

42*42+40*40=c*c

We move all terms to the left:

42*42+40*40-(c*c)=0

We add all the numbers together, and all the variables

-(+c*c)+42*42+40*40=0

We add all the numbers together, and all the variables

-(+c*c)+3364=0

We get rid of parentheses

-c*c+3364=0

Wy multiply elements

-1c^2+3364=0

a = -1; b = 0; c = +3364;
Δ = b2-4ac
Δ = 02-4·(-1)·3364
Δ = 13456
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{13456}=116$
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-116}{2*-1}=\frac{-116}{-2}
=+58
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+116}{2*-1}=\frac{116}{-2}
=-58
$