100=-16x^2+72x+35

Solution for 100=-16x^2+72x+35 equation:

100=-16x^2+72x+35

We move all terms to the left:

100-(-16x^2+72x+35)=0

We get rid of parentheses

16x^2-72x-35+100=0

We add all the numbers together, and all the variables

16x^2-72x+65=0

a = 16; b = -72; c = +65;
Δ = b2-4ac
Δ = -722-4·16·65
Δ = 1024
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1024}=32$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-72)-32}{2*16}=\frac{40}{32}
=1+1/4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-72)+32}{2*16}=\frac{104}{32}
=3+1/4
$