-16x^2+26x+11=21

Solution for -16x^2+26x+11=21 equation:

-16x^2+26x+11=21

We move all terms to the left:

-16x^2+26x+11-(21)=0

We add all the numbers together, and all the variables

-16x^2+26x-10=0

a = -16; b = 26; c = -10;
Δ = b2-4ac
Δ = 262-4·(-16)·(-10)
Δ = 36
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{36}=6$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(26)-6}{2*-16}=\frac{-32}{-32}
=1
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(26)+6}{2*-16}=\frac{-20}{-32}
=5/8
$