-0.8x^2+16x+1=69

Solution for -0.8x^2+16x+1=69 equation:

-0.8x^2+16x+1=69

We move all terms to the left:

-0.8x^2+16x+1-(69)=0

We add all the numbers together, and all the variables

-0.8x^2+16x-68=0

a = -0.8; b = 16; c = -68;
Δ = b2-4ac
Δ = 162-4·(-0.8)·(-68)
Δ = 38.4
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{-(16)-\sqrt{38.4}}{2*-0.8}=\frac{-16-\sqrt{38.4}}{-1.6}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(16)+\sqrt{38.4}}{2*-0.8}=\frac{-16+\sqrt{38.4}}{-1.6}
$