-7x+14-7x^2=0

Solution for -7x+14-7x^2=0 equation:

-7x+14-7x^2=0

a = -7; b = -7; c = +14;
Δ = b2-4ac
Δ = -72-4·(-7)·14
Δ = 441
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{441}=21$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-7)-21}{2*-7}=\frac{-14}{-14}
=1
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-7)+21}{2*-7}=\frac{28}{-14}
=-2
$