2.3x^2+x^2=80

Solution for 2.3x^2+x^2=80 equation:

2.3x^2+x^2=80

We move all terms to the left:

2.3x^2+x^2-(80)=0

We add all the numbers together, and all the variables

3.3x^2-80=0

a = 3.3; b = 0; c = -80;
Δ = b2-4ac
Δ = 02-4·3.3·(-80)
Δ = 1056
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{1056}=\sqrt{16*66}=\sqrt{16}*\sqrt{66}=4\sqrt{66}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4\sqrt{66}}{2*3.3}=\frac{0-4\sqrt{66}}{6.6}
=-\frac{4\sqrt{66}}{6.6}
=-\frac{2\sqrt{66}}{3.3}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4\sqrt{66}}{2*3.3}=\frac{0+4\sqrt{66}}{6.6}
=\frac{4\sqrt{66}}{6.6}
=\frac{2\sqrt{66}}{3.3}
$