b2-7b+9=0

Solution for b2-7b+9=0 equation:

b2-7b+9=0

We add all the numbers together, and all the variables

b^2-7b+9=0

a = 1; b = -7; c = +9;
Δ = b2-4ac
Δ = -72-4·1·9
Δ = 13
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{13}}{2*1}=\frac{7-\sqrt{13}}{2}
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-7)+\sqrt{13}}{2*1}=\frac{7+\sqrt{13}}{2}
$