a^2+8.4^2=9.2^2

Solution for a^2+8.4^2=9.2^2 equation:

a^2+8.4^2=9.2^2

We move all terms to the left:

a^2+8.4^2-(9.2^2)=0

We add all the numbers together, and all the variables

a^2-14.08=0

a = 1; b = 0; c = -14.08;
Δ = b2-4ac
Δ = 02-4·1·(-14.08)
Δ = 56.32
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-\sqrt{56.32}}{2*1}=\frac{0-\sqrt{56.32}}{2}
=-\frac{\sqrt{}}{2}
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{56.32}}{2*1}=\frac{0+\sqrt{56.32}}{2}
=\frac{\sqrt{}}{2}
$