42.4x^2-9=0

Solution for 42.4x^2-9=0 equation:

42.4x^2-9=0

a = 42.4; b = 0; c = -9;
Δ = b2-4ac
Δ = 02-4·42.4·(-9)
Δ = 1526.4
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-\sqrt{1526.4}}{2*42.4}=\frac{0-\sqrt{1526.4}}{84.8}
=-\frac{\sqrt{}}{84.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+\sqrt{1526.4}}{2*42.4}=\frac{0+\sqrt{1526.4}}{84.8}
=\frac{\sqrt{}}{84.8}
$