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(x-11)*(-x+9)=0

(x-11)*(-x+9)=0 equation

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Numerical solution:

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The solution

You have entered [src] 
(x - 11)*(-x + 9) = 0
(9−x)(x−11)=0\left(9 - x\right) \left(x - 11\right) = 0
Simplify
Detail solution
Expand the expression in the equation
(9−x)(x−11)=0\left(9 - x\right) \left(x - 11\right) = 0
We get the quadratic equation
−x2+20x−99=0- x^{2} + 20 x - 99 = 0
This equation is of the form
a*x^2 + b*x + c = 0

A quadratic equation can be solved
using the discriminant.
The roots of the quadratic equation:
x1=D−b2ax_{1} = \frac{\sqrt{D} - b}{2 a}
x2=−D−b2ax_{2} = \frac{- \sqrt{D} - b}{2 a}
where D = b^2 - 4*a*c - it is the discriminant.
Because
a=−1a = -1
b=20b = 20
c=−99c = -99
, then
D = b^2 - 4 * a * c = 

(20)^2 - 4 * (-1) * (-99) = 4

Because D > 0, then the equation has two roots.
x1 = (-b + sqrt(D)) / (2*a)

x2 = (-b - sqrt(D)) / (2*a)

or
x1=9x_{1} = 9
x2=11x_{2} = 11
The graph
051015202530-200100
Plot the graph f1(x)
Plot the graph f2(x)
Rapid solution [src] 
x1 = 9
x1=9x_{1} = 9 
x2 = 11
x2=11x_{2} = 11 
x2 = 11
Sum and product of roots [src] 
sum
9 + 11
9+119 + 11 
=
20
2020 
product
9*11
9⋅119 \cdot 11 
=
99
9999 
99
Numerical answer [src] 
x1 = 11.0
x2 = 9.0
x2 = 9.0
The graph
(x-11)*(-x+9)=0 equation
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