16x2+16x+4=81

Solution for 16x2+16x+4=81 equation:

16x^2+16x+4=81

We move all terms to the left:

16x^2+16x+4-(81)=0

We add all the numbers together, and all the variables

16x^2+16x-77=0

a = 16; b = 16; c = -77;
Δ = b2-4ac
Δ = 162-4·16·(-77)
Δ = 5184
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{5184}=72$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(16)-72}{2*16}=\frac{-88}{32}
=-2+3/4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(16)+72}{2*16}=\frac{56}{32}
=1+3/4
$