64.4756=-0.0041x^2+x+3.5

Solution for 64.4756=-0.0041x^2+x+3.5 equation:

64.4756=-0.0041x^2+x+3.5

We move all terms to the left:

64.4756-(-0.0041x^2+x+3.5)=0

We get rid of parentheses

0.0041x^2-x-3.5+64.4756=0

We add all the numbers together, and all the variables

0.0041x^2-1x+60.9756=0

a = 0.0041; b = -1; c = +60.9756;
Δ = b2-4ac
Δ = -12-4·0.0041·60.9756
Δ = 1.5999999991578E-7
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{-(-1)-\sqrt{1.5999999991578E-7}}{2*0.0041}=\frac{1-\sqrt{1.5999999991578E-7}}{0.0082}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1)+\sqrt{1.5999999991578E-7}}{2*0.0041}=\frac{1+\sqrt{1.5999999991578E-7}}{0.0082}
$