7-b(b=6)

Solution for 7-b(b=6) equation:

7-b(b=6)

We move all terms to the left:

7-b(b-(6))=0

We multiply parentheses

-b^2+6b+7=0

We add all the numbers together, and all the variables

-1b^2+6b+7=0

a = -1; b = 6; c = +7;
Δ = b2-4ac
Δ = 62-4·(-1)·7
Δ = 64
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{64}=8$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-8}{2*-1}=\frac{-14}{-2}
=+7
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+8}{2*-1}=\frac{2}{-2}
=-1
$