129=-16x^2+130x+3

Solution for 129=-16x^2+130x+3 equation:

129=-16x^2+130x+3

We move all terms to the left:

129-(-16x^2+130x+3)=0

We get rid of parentheses

16x^2-130x-3+129=0

We add all the numbers together, and all the variables

16x^2-130x+126=0

a = 16; b = -130; c = +126;
Δ = b2-4ac
Δ = -1302-4·16·126
Δ = 8836
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{8836}=94$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-130)-94}{2*16}=\frac{36}{32}
=1+1/8
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-130)+94}{2*16}=\frac{224}{32}
=7
$