b2-7b+8=0

Solution for b2-7b+8=0 equation:

b2-7b+8=0

We add all the numbers together, and all the variables

b^2-7b+8=0

a = 1; b = -7; c = +8;
Δ = b2-4ac
Δ = -72-4·1·8
Δ = 17
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-7)-\sqrt{17}}{2*1}=\frac{7-\sqrt{17}}{2}
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-7)+\sqrt{17}}{2*1}=\frac{7+\sqrt{17}}{2}
$