Mister Exam

Other calculators

x^2-4x+5=0

x^2-4x+5=0 equation

The teacher will be very surprised to see your correct solution 😉

v

Numerical solution:

Do search numerical solution at [, ]

The solution

You have entered [src] 
 2              
x  - 4*x + 5 = 0
(x2−4x)+5=0\left(x^{2} - 4 x\right) + 5 = 0
Simplify
Detail solution
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=−4b = -4
c=5c = 5
, then
D = b^2 - 4 * a * c = 

(-4)^2 - 4 * (1) * (5) = -4

Because D<0, then the equation
has no real roots,
but complex roots is exists.
x1 = (-b + sqrt(D)) / (2*a)

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

or
x1=2+ix_{1} = 2 + i
x2=2−ix_{2} = 2 - i
Vieta's Theorem
it is reduced quadratic equation
px+q+x2=0p x + q + x^{2} = 0
where
p=bap = \frac{b}{a}
p=−4p = -4
q=caq = \frac{c}{a}
q=5q = 5
Vieta Formulas
x1+x2=−px_{1} + x_{2} = - p
x1x2=qx_{1} x_{2} = q
x1+x2=4x_{1} + x_{2} = 4
x1x2=5x_{1} x_{2} = 5
The graph
0123456789-3-2-1020
Plot the graph f1(x)
Plot the graph f2(x)
Sum and product of roots [src] 
sum
2 - I + 2 + I
(2−i)+(2+i)\left(2 - i\right) + \left(2 + i\right) 
=
4
44 
product
(2 - I)*(2 + I)
(2−i)(2+i)\left(2 - i\right) \left(2 + i\right) 
=
5
55 
5
Rapid solution [src] 
x1 = 2 - I
x1=2−ix_{1} = 2 - i 
x2 = 2 + I
x2=2+ix_{2} = 2 + i 
x2 = 2 + i
Numerical answer [src] 
x1 = 2.0 - 1.0*i
x2 = 2.0 + 1.0*i
x2 = 2.0 + 1.0*i
The graph
x^2-4x+5=0 equation
    © Mister Exam – Calculator