4x^2+8x-16=5

Solution for 4x^2+8x-16=5 equation:

4x^2+8x-16=5

We move all terms to the left:

4x^2+8x-16-(5)=0

We add all the numbers together, and all the variables

4x^2+8x-21=0

a = 4; b = 8; c = -21;
Δ = b2-4ac
Δ = 82-4·4·(-21)
Δ = 400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{400}=20$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8)-20}{2*4}=\frac{-28}{8}
=-3+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+20}{2*4}=\frac{12}{8}
=1+1/2
$